diff --git a/addons/hr_holidays/static/tests/thread_icon_patch_tests.js b/addons/hr_holidays/static/tests/thread_icon_patch_tests.js
index aee87d6bcf6..b13b94c3306 100644
--- a/addons/hr_holidays/static/tests/thread_icon_patch_tests.js
+++ b/addons/hr_holidays/static/tests/thread_icon_patch_tests.js
@@ -21,7 +21,7 @@ QUnit.test("thread icon of a chat when correspondent is on leave & online", asyn
     await openDiscuss();
     assert.containsOnce(
         $,
-        ".o-mail-DiscussCategoryItem:contains(Demo) .o-mail-ThreadIcon .fa-plane[title='Online']"
+        ".o-mail-DiscussSidebarChannel:contains(Demo) .o-mail-ThreadIcon .fa-plane[title='Online']"
     );
 });
 
@@ -42,7 +42,7 @@ QUnit.test("thread icon of a chat when correspondent is on leave & away", async
     await openDiscuss();
     assert.containsOnce(
         $,
-        ".o-mail-DiscussCategoryItem:contains(Demo) .o-mail-ThreadIcon .fa-plane[title='Away']"
+        ".o-mail-DiscussSidebarChannel:contains(Demo) .o-mail-ThreadIcon .fa-plane[title='Away']"
     );
 });
 
@@ -63,6 +63,6 @@ QUnit.test("thread icon of a chat when correspondent is on leave & offline", asy
     await openDiscuss();
     assert.containsOnce(
         $,
-        ".o-mail-DiscussCategoryItem:contains(Demo) .o-mail-ThreadIcon .fa-plane[title='Out of office']"
+        ".o-mail-DiscussSidebarChannel:contains(Demo) .o-mail-ThreadIcon .fa-plane[title='Out of office']"
     );
 });
diff --git a/addons/im_livechat/static/src/core/store_service_patch.js b/addons/im_livechat/static/src/core/store_service_patch.js
index 350d8a2fe7a..4af864acd1d 100644
--- a/addons/im_livechat/static/src/core/store_service_patch.js
+++ b/addons/im_livechat/static/src/core/store_service_patch.js
@@ -9,7 +9,7 @@ patch(Store.prototype, "im_livechat", {
     setup(env) {
         this._super(env);
         this.discuss.livechat = {
-            extraClass: "o-mail-DiscussCategory-livechat",
+            extraClass: "o-mail-DiscussSidebarCategory-livechat",
             id: "livechat",
             name: _t("Livechat"),
             isOpen: false,
diff --git a/addons/im_livechat/static/src/discuss_app/discuss_sidebar_categories_livechat.js b/addons/im_livechat/static/src/discuss_app/discuss_sidebar_categories_livechat.js
new file mode 100644
index 00000000000..c4ee7b70c97
--- /dev/null
+++ b/addons/im_livechat/static/src/discuss_app/discuss_sidebar_categories_livechat.js
@@ -0,0 +1,13 @@
+/* @odoo-module */
+
+import { discussSidebarCategoriesRegistry } from "@mail/discuss/core/web/discuss_sidebar_categories";
+
+discussSidebarCategoriesRegistry.add(
+    "livechats",
+    {
+        predicate: (store) =>
+            store.discuss.livechat.threads.some((localId) => store.threads[localId]?.is_pinned),
+        value: (store) => store.discuss.livechat,
+    },
+    { sequence: 20 }
+);
diff --git a/addons/im_livechat/static/src/discuss_app/sidebar_patch.js b/addons/im_livechat/static/src/discuss_app/sidebar_patch.js
deleted file mode 100644
index ef7ab8fc698..00000000000
--- a/addons/im_livechat/static/src/discuss_app/sidebar_patch.js
+++ /dev/null
@@ -1,13 +0,0 @@
-/* @odoo-module */
-
-import { Sidebar } from "@mail/core/web/sidebar";
-
-import { patch } from "@web/core/utils/patch";
-
-patch(Sidebar.prototype, "im_livechat", {
-    get shouldDisplayLivechatCategory() {
-        return this.store.discuss.livechat.threads.some(
-            (localId) => this.store.threads[localId]?.is_pinned
-        );
-    },
-});
diff --git a/addons/im_livechat/static/src/discuss_app/sidebar_patch.xml b/addons/im_livechat/static/src/discuss_app/sidebar_patch.xml
deleted file mode 100644
index 442cc8ed2f7..00000000000
--- a/addons/im_livechat/static/src/discuss_app/sidebar_patch.xml
+++ /dev/null
@@ -1,10 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<templates>
-    <t t-name="im_livechat.DiscussSidebar" t-inherit="mail.DiscussSidebar" t-inherit-mode="extension" owl="1">
-        <xpath expr="//*[@name='chatCategory']" position="before">
-            <t t-if="shouldDisplayLivechatCategory" t-call="mail.DiscussCategory">
-                <t t-set="category" t-value="store.discuss.livechat"/>
-            </t>
-        </xpath>
-    </t>
-</templates>
diff --git a/addons/im_livechat/static/tests/channel_invite_tests.js b/addons/im_livechat/static/tests/channel_invite_tests.js
index ada709ba11b..0089557aa1e 100644
--- a/addons/im_livechat/static/tests/channel_invite_tests.js
+++ b/addons/im_livechat/static/tests/channel_invite_tests.js
@@ -98,11 +98,11 @@ QUnit.test("Partners invited most frequently by the current user come first", as
 
     const { openDiscuss } = await start();
     await openDiscuss();
-    await click(".o-mail-DiscussCategoryItem:contains(Visitor #1)");
+    await click(".o-mail-DiscussSidebarChannel:contains(Visitor #1)");
     await click("button[title='Add Users']");
     await click(".o-discuss-ChannelInvitation-selectable:contains(John) input");
     await click("button:contains(Invite)");
-    await click(".o-mail-DiscussCategoryItem:contains(Visitor #2)");
+    await click(".o-mail-DiscussSidebarChannel:contains(Visitor #2)");
     await click("button[title='Add Users']");
     const partnerSuggestions = document.querySelectorAll(".o-discuss-ChannelInvitation-selectable");
     assert.ok(partnerSuggestions[0].textContent.includes("John"));
diff --git a/addons/im_livechat/static/tests/discuss_patch_tests.js b/addons/im_livechat/static/tests/discuss_patch_tests.js
index 5ca22855a43..180e185ed2f 100644
--- a/addons/im_livechat/static/tests/discuss_patch_tests.js
+++ b/addons/im_livechat/static/tests/discuss_patch_tests.js
@@ -85,7 +85,7 @@ QUnit.test("add livechat in the sidebar on visitor sending first message", async
     });
     const { env, openDiscuss } = await start();
     await openDiscuss();
-    assert.containsNone($, ".o-mail-DiscussCategory-livechat");
+    assert.containsNone($, ".o-mail-DiscussSidebarCategory-livechat");
     // simulate livechat visitor sending a message
     const [channel] = pyEnv["discuss.channel"].searchRead([["id", "=", channelId]]);
     await afterNextRender(async () =>
@@ -95,11 +95,14 @@ QUnit.test("add livechat in the sidebar on visitor sending first message", async
             message_content: "new message",
         })
     );
-    assert.containsOnce($, ".o-mail-DiscussCategory-livechat");
-    assert.containsOnce($, ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem");
+    assert.containsOnce($, ".o-mail-DiscussSidebarCategory-livechat");
     assert.containsOnce(
         $,
-        ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem:contains(Visitor (Belgium))"
+        ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel"
+    );
+    assert.containsOnce(
+        $,
+        ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel:contains(Visitor (Belgium))"
     );
 });
 
@@ -175,14 +178,14 @@ QUnit.test(
         ]);
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.strictEqual($(".o-mail-DiscussCategoryItem:eq(0)").text(), "Visitor 12");
-        assert.strictEqual($(".o-mail-DiscussCategoryItem:eq(1)").text(), "Visitor 11");
+        assert.strictEqual($(".o-mail-DiscussSidebarChannel:eq(0)").text(), "Visitor 12");
+        assert.strictEqual($(".o-mail-DiscussSidebarChannel:eq(1)").text(), "Visitor 11");
         // post a new message on the last channel
-        await click(".o-mail-DiscussCategoryItem:eq(1)");
+        await click(".o-mail-DiscussSidebarChannel:eq(1)");
         await insertText(".o-mail-Composer-input", "Blabla");
         await click(".o-mail-Composer-send");
-        assert.containsN($, ".o-mail-DiscussCategoryItem", 2);
-        assert.strictEqual($(".o-mail-DiscussCategoryItem:eq(0)").text(), "Visitor 11");
-        assert.strictEqual($(".o-mail-DiscussCategoryItem:eq(1)").text(), "Visitor 12");
+        assert.containsN($, ".o-mail-DiscussSidebarChannel", 2);
+        assert.strictEqual($(".o-mail-DiscussSidebarChannel:eq(0)").text(), "Visitor 11");
+        assert.strictEqual($(".o-mail-DiscussSidebarChannel:eq(1)").text(), "Visitor 12");
     }
 );
diff --git a/addons/im_livechat/static/tests/go_to_oldest_unread_thread_tests.js b/addons/im_livechat/static/tests/go_to_oldest_unread_thread_tests.js
index 56f21f748da..a1f2c0b29b7 100644
--- a/addons/im_livechat/static/tests/go_to_oldest_unread_thread_tests.js
+++ b/addons/im_livechat/static/tests/go_to_oldest_unread_thread_tests.js
@@ -70,21 +70,18 @@ QUnit.test("tab on discuss composer goes to oldest unread livechat", async (asse
     const { openDiscuss } = await start();
     await openDiscuss(channelIds[0]);
 
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem.o-active:contains(Visitor 11)");
-    assert.containsOnce(
-        $,
-        ".o-mail-Composer-footer:contains(Tab to next livechat)"
-    );
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel.o-active:contains(Visitor 11)");
+    assert.containsOnce($, ".o-mail-Composer-footer:contains(Tab to next livechat)");
     await afterNextRender(() => {
         document.querySelector(".o-mail-Composer-input").focus();
         triggerHotkey("Tab");
     });
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem.o-active:contains(Visitor 13)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel.o-active:contains(Visitor 13)");
     await afterNextRender(() => {
         document.querySelector(".o-mail-Composer-input").focus();
         triggerHotkey("Tab");
     });
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem.o-active:contains(Visitor 12)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel.o-active:contains(Visitor 12)");
 });
 
 QUnit.test("switching to folded chat window unfolds it", async (assert) => {
@@ -231,7 +228,7 @@ QUnit.test("tab on composer doesn't switch thread if user is typing", async (ass
     await insertText(".o-mail-Composer-input", "Hello, ");
     triggerHotkey("Tab");
     await nextTick();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem.o-active:contains(Visitor 11)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel.o-active:contains(Visitor 11)");
 });
 
 QUnit.test("tab on composer doesn't switch thread if no unread thread", async (assert) => {
@@ -264,5 +261,5 @@ QUnit.test("tab on composer doesn't switch thread if no unread thread", async (a
     document.querySelector(".o-mail-Composer-input").focus();
     triggerHotkey("Tab");
     await nextTick();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem.o-active:contains(Visitor 11)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel.o-active:contains(Visitor 11)");
 });
diff --git a/addons/im_livechat/static/tests/sidebar_patch_tests.js b/addons/im_livechat/static/tests/sidebar_patch_tests.js
index fd659e80ca7..4f18a3b3b64 100644
--- a/addons/im_livechat/static/tests/sidebar_patch_tests.js
+++ b/addons/im_livechat/static/tests/sidebar_patch_tests.js
@@ -20,8 +20,8 @@ QUnit.test("Unknown visitor", async (assert) => {
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussSidebar .o-mail-DiscussCategory-livechat");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(Visitor 11)");
+    assert.containsOnce($, ".o-mail-DiscussSidebar .o-mail-DiscussSidebarCategory-livechat");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(Visitor 11)");
 });
 
 QUnit.test("Known user with country", async (assert) => {
@@ -44,7 +44,7 @@ QUnit.test("Known user with country", async (assert) => {
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(Jean (Belgium))");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(Jean (Belgium))");
 });
 
 QUnit.test("Do not show channel when visitor is typing", async (assert) => {
@@ -71,7 +71,7 @@ QUnit.test("Do not show channel when visitor is typing", async (assert) => {
     });
     const { env, openDiscuss } = await start();
     await openDiscuss();
-    assert.containsNone($, ".o-mail-DiscussCategory-livechat");
+    assert.containsNone($, ".o-mail-DiscussSidebarCategory-livechat");
     // simulate livechat visitor typing
     const channel = pyEnv["discuss.channel"].searchRead([["id", "=", channelId]])[0];
     await env.services.rpc("/im_livechat/notify_typing", {
@@ -82,7 +82,7 @@ QUnit.test("Do not show channel when visitor is typing", async (assert) => {
         uuid: channel.uuid,
     });
     await nextTick();
-    assert.containsNone($, ".o-mail-DiscussCategory-livechat");
+    assert.containsNone($, ".o-mail-DiscussSidebarCategory-livechat");
 });
 
 QUnit.test("Close should update the value on the server", async (assert) => {
@@ -109,7 +109,7 @@ QUnit.test("Close should update the value on the server", async (assert) => {
         [[currentUserId]]
     );
     assert.ok(initalSettings.is_discuss_sidebar_category_livechat_open);
-    await click(".o-mail-DiscussCategory-livechat .btn");
+    await click(".o-mail-DiscussSidebarCategory-livechat .btn");
     const newSettings = await env.services.orm.call(
         "res.users.settings",
         "_find_or_create_for_user",
@@ -142,7 +142,7 @@ QUnit.test("Open should update the value on the server", async (assert) => {
         [[currentUserId]]
     );
     assert.notOk(initalSettings.is_discuss_sidebar_category_livechat_open);
-    await click(".o-mail-DiscussCategory-livechat .btn");
+    await click(".o-mail-DiscussSidebarCategory-livechat .btn");
     const newSettings = await env.services.orm.call(
         "res.users.settings",
         "_find_or_create_for_user",
@@ -168,7 +168,10 @@ QUnit.test("Open from the bus", async (assert) => {
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsNone($, ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem");
+    assert.containsNone(
+        $,
+        ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel"
+    );
     await afterNextRender(() => {
         pyEnv["bus.bus"]._sendone(pyEnv.currentPartner, "mail.record/insert", {
             "res.users.settings": {
@@ -177,7 +180,10 @@ QUnit.test("Open from the bus", async (assert) => {
             },
         });
     });
-    assert.containsOnce($, ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem");
+    assert.containsOnce(
+        $,
+        ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel"
+    );
 });
 
 QUnit.test("Close from the bus", async (assert) => {
@@ -197,7 +203,10 @@ QUnit.test("Close from the bus", async (assert) => {
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem");
+    assert.containsOnce(
+        $,
+        ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel"
+    );
     await afterNextRender(() => {
         pyEnv["bus.bus"]._sendone(pyEnv.currentPartner, "mail.record/insert", {
             "res.users.settings": {
@@ -206,7 +215,10 @@ QUnit.test("Close from the bus", async (assert) => {
             },
         });
     });
-    assert.containsNone($, ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem");
+    assert.containsNone(
+        $,
+        ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel"
+    );
 });
 
 QUnit.test("Smiley face avatar for an anonymous livechat item", async (assert) => {
@@ -223,7 +235,8 @@ QUnit.test("Smiley face avatar for an anonymous livechat item", async (assert) =
     const { openDiscuss } = await start();
     await openDiscuss();
     assert.strictEqual(
-        $(".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem img")[0].dataset.src,
+        $(".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel img")[0].dataset
+            .src,
         "/mail/static/src/img/smiley/avatar.jpg"
     );
 });
@@ -242,7 +255,8 @@ QUnit.test("Partner profile picture for livechat item linked to a partner", asyn
     const { openDiscuss } = await start();
     await openDiscuss(channelId);
     assert.strictEqual(
-        $(".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem img")[0].dataset.src,
+        $(".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel img")[0].dataset
+            .src,
         `/web/image/res.partner/${partnerId}/avatar_128`
     );
 });
@@ -269,7 +283,7 @@ QUnit.test("No counter if the category is unfolded and with unread messages", as
     await openDiscuss();
     assert.containsNone(
         $,
-        ".o-mail-DiscussCategory-livechat .o-mail-Discuss-category-counter",
+        ".o-mail-DiscussSidebarCategory-livechat .o-mail-Discuss-category-counter",
         "should not have a counter if the category is unfolded and with unread messages"
     );
 });
@@ -293,7 +307,7 @@ QUnit.test("No counter if category is folded and without unread messages", async
     await openDiscuss();
     assert.containsNone(
         $,
-        ".o-mail-DiscussCategory-livechat .o-discuss-badge",
+        ".o-mail-DiscussSidebarCategory-livechat .o-discuss-badge",
         "should not have a counter if the category is unfolded and with unread messages"
     );
 });
@@ -324,7 +338,10 @@ QUnit.test(
         });
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.strictEqual($(".o-mail-DiscussCategory-livechat .o-discuss-badge").text(), "1");
+        assert.strictEqual(
+            $(".o-mail-DiscussSidebarCategory-livechat .o-discuss-badge").text(),
+            "1"
+        );
     }
 );
 
@@ -347,12 +364,12 @@ QUnit.test("Close manually by clicking the title", async (assert) => {
     await openDiscuss();
     assert.containsOnce(
         $,
-        ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem",
+        ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel",
         "Category is unfolded initially"
     );
     // fold the livechat category
-    await click(".o-mail-DiscussCategory-livechat .btn");
-    assert.containsNone($, ".o-mail-DiscussCategoryItem");
+    await click(".o-mail-DiscussSidebarCategory-livechat .btn");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel");
 });
 
 QUnit.test("Open manually by clicking the title", async (assert) => {
@@ -374,12 +391,15 @@ QUnit.test("Open manually by clicking the title", async (assert) => {
     await openDiscuss();
     assert.containsNone(
         $,
-        ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem",
+        ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel",
         "Category is folded initially"
     );
     // open the livechat category
-    await click(".o-mail-DiscussCategory-livechat .btn");
-    assert.containsOnce($, ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem");
+    await click(".o-mail-DiscussSidebarCategory-livechat .btn");
+    assert.containsOnce(
+        $,
+        ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel"
+    );
 });
 
 QUnit.test("Category item should be invisible if the category is closed", async (assert) => {
@@ -395,9 +415,15 @@ QUnit.test("Category item should be invisible if the category is closed", async
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem");
-    await click(".o-mail-DiscussCategory-livechat .btn");
-    assert.containsNone($, ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem");
+    assert.containsOnce(
+        $,
+        ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel"
+    );
+    await click(".o-mail-DiscussSidebarCategory-livechat .btn");
+    assert.containsNone(
+        $,
+        ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel"
+    );
 });
 
 QUnit.test(
@@ -415,14 +441,20 @@ QUnit.test(
         });
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.containsOnce($, ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem");
-        await click(".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem");
         assert.containsOnce(
             $,
-            ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem.o-active"
+            ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel"
+        );
+        await click(".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel");
+        assert.containsOnce(
+            $,
+            ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel.o-active"
+        );
+        await click(".o-mail-DiscussSidebarCategory-livechat .btn");
+        assert.containsOnce(
+            $,
+            ".o-mail-DiscussSidebarCategory-livechat + .o-mail-DiscussSidebarChannel"
         );
-        await click(".o-mail-DiscussCategory-livechat .btn");
-        assert.containsOnce($, ".o-mail-DiscussCategory-livechat + .o-mail-DiscussCategoryItem");
     }
 );
 
@@ -443,7 +475,7 @@ QUnit.test("Clicking on unpin button unpins the channel", async (assert) => {
         },
     });
     await openDiscuss();
-    await click(".o-mail-DiscussCategoryItem [title='Unpin Conversation']");
+    await click(".o-mail-DiscussSidebarChannel [title='Unpin Conversation']");
     assert.verifySteps(["You unpinned your conversation with Visitor 11"]);
 });
 
@@ -469,5 +501,5 @@ QUnit.test("Message unread counter", async (assert) => {
             uuid: pyEnv["discuss.channel"].searchRead([["id", "=", channelId]])[0].uuid,
         })
     );
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem .badge:contains(1)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel .badge:contains(1)");
 });
diff --git a/addons/mail/static/src/core/common/store_service.js b/addons/mail/static/src/core/common/store_service.js
index 2de62d52861..b1374faa5b1 100644
--- a/addons/mail/static/src/core/common/store_service.js
+++ b/addons/mail/static/src/core/common/store_service.js
@@ -107,7 +107,7 @@ export class Store {
         isActive: false,
         threadLocalId: null,
         channels: {
-            extraClass: "o-mail-DiscussCategory-channel",
+            extraClass: "o-mail-DiscussSidebarCategory-channel",
             id: "channels",
             name: _t("Channels"),
             isOpen: false,
@@ -118,7 +118,7 @@ export class Store {
             threads: [], // list of ids
         },
         chats: {
-            extraClass: "o-mail-DiscussCategory-chat",
+            extraClass: "o-mail-DiscussSidebarCategory-chat",
             id: "chats",
             name: _t("Direct messages"),
             isOpen: false,
diff --git a/addons/mail/static/src/core/common/thread_service.js b/addons/mail/static/src/core/common/thread_service.js
index 612b98072cf..1688cc7e461 100644
--- a/addons/mail/static/src/core/common/thread_service.js
+++ b/addons/mail/static/src/core/common/thread_service.js
@@ -1022,7 +1022,7 @@ export class ThreadService {
         return thread.message_needaction_counter;
     }
 
-    getDiscussCategoryCounter(categoryId) {
+    getDiscussSidebarCategoryCounter(categoryId) {
         return this.store.discuss[categoryId].threads.reduce((acc, threadLocalId) => {
             const channel = this.store.threads[threadLocalId];
             if (categoryId === "channels") {
diff --git a/addons/mail/static/src/core/web/discuss_patch.js b/addons/mail/static/src/core/web/discuss_patch.js
index 84a36fd9a07..da82acd6f8a 100644
--- a/addons/mail/static/src/core/web/discuss_patch.js
+++ b/addons/mail/static/src/core/web/discuss_patch.js
@@ -1,11 +1,7 @@
 /* @odoo-module */
 
 import { Discuss } from "@mail/core/common/discuss";
+import { DiscussSidebar } from "@mail/core/web/discuss_sidebar";
 import { MessagingMenu } from "@mail/core/web/messaging_menu";
-import { Sidebar } from "@mail/core/web/sidebar";
 
-import { patch } from "@web/core/utils/patch";
-
-patch(Discuss, "mail/core/web", {
-    components: { ...Discuss.components, Sidebar, MessagingMenu },
-});
+Object.assign(Discuss.components, { DiscussSidebar, MessagingMenu });
diff --git a/addons/mail/static/src/core/web/discuss_patch.xml b/addons/mail/static/src/core/web/discuss_patch.xml
index ab88bf959e4..f1674c98d33 100644
--- a/addons/mail/static/src/core/web/discuss_patch.xml
+++ b/addons/mail/static/src/core/web/discuss_patch.xml
@@ -2,7 +2,7 @@
 <templates xml:space="preserve">
     <t t-inherit="mail.Discuss" t-inherit-mode="extension" owl="1">
         <xpath expr="//*[@t-ref='mobileTopbar']" position="before">
-            <Sidebar t-if="!props.public and !ui.isSmall"/>
+            <DiscussSidebar t-if="!ui.isSmall"/>
         </xpath>
         <xpath expr="//*[@t-ref='root']" position="inside">
             <MessagingMenu t-if="ui.isSmall"/>
diff --git a/addons/mail/static/src/core/web/sidebar.dark.scss b/addons/mail/static/src/core/web/discuss_sidebar.dark.scss
similarity index 99%
rename from addons/mail/static/src/core/web/sidebar.dark.scss
rename to addons/mail/static/src/core/web/discuss_sidebar.dark.scss
index dc27077d4c8..d57731b58fc 100644
--- a/addons/mail/static/src/core/web/sidebar.dark.scss
+++ b/addons/mail/static/src/core/web/discuss_sidebar.dark.scss
@@ -1,4 +1,3 @@
-
 .o-mail-DiscussSidebar-item {
     &:hover, &.o-active {
         background-color: $o-gray-100 !important;
diff --git a/addons/mail/static/src/core/web/discuss_sidebar.js b/addons/mail/static/src/core/web/discuss_sidebar.js
new file mode 100644
index 00000000000..75a8ee121c9
--- /dev/null
+++ b/addons/mail/static/src/core/web/discuss_sidebar.js
@@ -0,0 +1,27 @@
+/* @odoo-module */
+
+import { useStore } from "@mail/core/common/messaging_hook";
+
+import { Component } from "@odoo/owl";
+
+import { registry } from "@web/core/registry";
+
+export const discussSidebarItemsRegistry = registry.category("mail.discuss_sidebar_items");
+
+/**
+ * @typedef {Object} Props
+ * @extends {Component<Props, Env>}
+ */
+export class DiscussSidebar extends Component {
+    static template = "mail.DiscussSidebar";
+    static props = {};
+    static components = {};
+
+    setup() {
+        this.store = useStore();
+    }
+
+    get discussSidebarItems() {
+        return discussSidebarItemsRegistry.getAll();
+    }
+}
diff --git a/addons/mail/static/src/core/web/discuss_sidebar.scss b/addons/mail/static/src/core/web/discuss_sidebar.scss
new file mode 100644
index 00000000000..a8161683a4e
--- /dev/null
+++ b/addons/mail/static/src/core/web/discuss_sidebar.scss
@@ -0,0 +1,13 @@
+.o-mail-DiscussSidebar {
+    width: 300px;
+}
+
+.o-mail-DiscussSidebar-badge {
+    padding: 3px 6px;
+}
+
+.o-mail-DiscussSidebar-item {
+    &:hover, &.o-active {
+        background-color: $o-gray-200 !important;
+    }
+}
diff --git a/addons/mail/static/src/core/web/discuss_sidebar.xml b/addons/mail/static/src/core/web/discuss_sidebar.xml
new file mode 100644
index 00000000000..eb21e02f334
--- /dev/null
+++ b/addons/mail/static/src/core/web/discuss_sidebar.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<templates xml:space="preserve">
+    <t t-name="mail.DiscussSidebar" owl="1">
+        <div class="o-mail-DiscussSidebar d-flex flex-column overflow-auto flex-shrink-0 h-100 pt-3 border-end bg-view">
+            <t t-foreach="discussSidebarItems" t-as="item" t-key="item_index" t-component="item"/>
+        </div>
+    </t>
+</templates>
diff --git a/addons/mail/static/src/core/web/discuss_sidebar_mailboxes.js b/addons/mail/static/src/core/web/discuss_sidebar_mailboxes.js
new file mode 100644
index 00000000000..9a475b02540
--- /dev/null
+++ b/addons/mail/static/src/core/web/discuss_sidebar_mailboxes.js
@@ -0,0 +1,37 @@
+/* @odoo-module */
+
+import { useStore } from "@mail/core/common/messaging_hook";
+import { ThreadIcon } from "@mail/core/common/thread_icon";
+import { discussSidebarItemsRegistry } from "@mail/core/web/discuss_sidebar";
+
+import { Component, useState } from "@odoo/owl";
+
+import { useService } from "@web/core/utils/hooks";
+import { markEventHandled } from "@web/core/utils/misc";
+
+/**
+ * @typedef {Object} Props
+ * @extends {Component<Props, Env>}
+ */
+export class DiscussSidebarMailboxes extends Component {
+    static template = "mail.DiscussSidebarMailboxes";
+    static props = {};
+    static components = { ThreadIcon };
+
+    setup() {
+        this.store = useStore();
+        /** @type {import("@mail/core/common/thread_service").ThreadService} */
+        this.threadService = useState(useService("mail.thread"));
+    }
+
+    /**
+     * @param {MouseEvent} ev
+     * @param {import("@mail/core/common/thread_model").Thread} thread
+     */
+    openThread(ev, thread) {
+        markEventHandled(ev, "sidebar.openThread");
+        this.threadService.setDiscussThread(thread);
+    }
+}
+
+discussSidebarItemsRegistry.add("mailbox", DiscussSidebarMailboxes, { sequence: 20 });
diff --git a/addons/mail/static/src/core/web/discuss_sidebar_mailboxes.xml b/addons/mail/static/src/core/web/discuss_sidebar_mailboxes.xml
new file mode 100644
index 00000000000..1649999687e
--- /dev/null
+++ b/addons/mail/static/src/core/web/discuss_sidebar_mailboxes.xml
@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<templates xml:space="preserve">
+
+    <t t-name="mail.DiscussSidebarMailboxes" owl="1">
+        <div class="d-flex flex-column flex-grow-0">
+            <t t-call="mail.Mailbox">
+                <t t-set="mailbox" t-value="store.discuss.inbox"/>
+            </t>
+            <t t-call="mail.Mailbox">
+                <t t-set="mailbox" t-value="store.discuss.starred"/>
+            </t>
+            <t t-call="mail.Mailbox">
+                <t t-set="mailbox" t-value="store.discuss.history"/>
+            </t>
+        </div>
+    </t>
+
+    <t t-name="mail.Mailbox" owl="1">
+        <button
+            class="o-mail-DiscussSidebar-item btn d-flex align-items-center py-1 px-0 border-0 rounded-0 fw-normal text-reset"
+            t-att-class="{
+                'o-bg-inherit': mailbox.localId !== store.discuss.threadLocalId,
+                'o-active': mailbox.localId === store.discuss.threadLocalId,
+            }"
+            t-on-click="(ev) => this.openThread(ev, mailbox)"
+        >
+            <ThreadIcon className="'ms-4 me-2 o-bg-inherit'" thread="mailbox"/>
+            <div class="me-2 text-truncate" t-esc="mailbox.name"/>
+            <div t-attf-class="flex-grow-1 {{ mailbox.counter === 0 ? 'me-3': '' }}"/>
+            <span
+                t-if="mailbox.counter > 0"
+                class="o-mail-DiscussSidebar-badge o-discuss-badge badge rounded-pill ms-1 me-3 fw-bold"
+                t-att-class="{ 'bg-400 text-light': mailbox.id === 'starred' }"
+                t-esc="mailbox.counter"
+            />
+        </button>
+    </t>
+
+</templates>
diff --git a/addons/mail/static/src/core/web/sidebar.scss b/addons/mail/static/src/core/web/sidebar.scss
deleted file mode 100644
index 5698e6441bd..00000000000
--- a/addons/mail/static/src/core/web/sidebar.scss
+++ /dev/null
@@ -1,32 +0,0 @@
-.o-mail-DiscussSidebar {
-    width: 300px;
-
-    .o-mail-DiscussCategory-icon {
-        width: 15px;
-        height: 15px;
-    }
-
-    .o-mail-DiscussCategory-im-status {
-        transform: scale(0.75);
-    }
-}
-
-.o-mail-DiscussSidebar-badge {
-    padding: 3px 6px;
-}
-
-.o-mail-DiscussSidebar-item {
-    &:hover, &.o-active {
-        background-color: $o-gray-200 !important;
-    }
-
-    &:hover .o-mail-DiscussCategoryItem-commands {
-        display: flex !important;
-    }
-}
-
-.o-mail-DiscussCategoryItem-threadIcon {
-    font-size: xx-small;
-    width: 13px;
-    height: 13px;
-}
diff --git a/addons/mail/static/src/core/web/sidebar.xml b/addons/mail/static/src/core/web/sidebar.xml
deleted file mode 100644
index 5a719400a1b..00000000000
--- a/addons/mail/static/src/core/web/sidebar.xml
+++ /dev/null
@@ -1,104 +0,0 @@
-<?xml version="1.0" encoding="UTF-8" ?>
-<templates xml:space="preserve">
-
-<t t-name="mail.DiscussSidebar" owl="1">
-    <div class="o-mail-DiscussSidebar d-flex flex-column overflow-auto flex-shrink-0 h-100 pt-3 border-end bg-view">
-        <div class="d-flex flex-column flex-grow-0" t-ref="mailboxes">
-            <t t-call="mail.Mailbox">
-                <t t-set="mailbox" t-value="store.discuss.inbox"/>
-            </t>
-            <t t-call="mail.Mailbox">
-                <t t-set="mailbox" t-value="store.discuss.starred"/>
-            </t>
-            <t t-call="mail.Mailbox">
-                <t t-set="mailbox" t-value="store.discuss.history"/>
-            </t>
-        </div>
-        <hr class="w-100 opacity-0"/>
-        <input t-if="hasQuickSearch" class="form-control mx-4 mb-2 rounded-3 w-auto" placeholder="Quick search..." t-model="state.quickSearchVal"/>
-        <t t-call="mail.DiscussCategory">
-            <t t-set="category" t-value="store.discuss.channels"/>
-        </t>
-        <t name="chatCategory" t-call="mail.DiscussCategory">
-            <t t-set="category" t-value="store.discuss.chats"/>
-        </t>
-    </div>
-</t>
-
-<t t-name="mail.Mailbox" owl="1">
-    <button class="o-mail-DiscussSidebar-item btn d-flex align-items-center py-1 px-0 border-0 rounded-0 fw-normal text-reset"
-        t-att-class="{
-            'o-bg-inherit': mailbox.localId !== store.discuss.threadLocalId,
-            'o-active': mailbox.localId === store.discuss.threadLocalId,
-        }"
-        t-on-click="(ev) => this.openThread(ev, mailbox)"
-    >
-        <ThreadIcon className="'ms-4 me-2 o-bg-inherit'" thread="mailbox"/>
-        <div class="me-2 text-truncate">
-            <t t-esc="mailbox.name"/>
-        </div>
-        <div t-attf-class="flex-grow-1 {{ mailbox.counter === 0 ? 'me-3': '' }}"/>
-        <div t-if="mailbox.counter > 0">
-            <span t-attf-class="o-mail-DiscussSidebar-badge badge rounded-pill o-discuss-badge {{ mailbox.id === 'starred' ? 'bg-400 text-light' : '' }} ms-1 me-3 fw-bold" t-esc="mailbox.counter"/>
-        </div>
-    </button>
-</t>
-
-<t t-name="mail.DiscussCategory" owl="1">
-    <t t-set="hover_class" t-value="'btn p-0 text-start text-700 opacity-100-hover opacity-75'"/>
-    <div class="o-mail-DiscussCategory d-flex align-items-center my-1" t-att-class="category.extraClass">
-        <div t-attf-class="d-flex align-items-baseline mx-1 {{ hover_class }}" t-on-click="() => this.toggleCategory(category)">
-            <i class="o-mail-DiscussCategory-icon small me-1" t-att-class="category.isOpen ? 'oi oi-chevron-down' : 'oi oi-chevron-right'"/>
-            <span class="btn-sm p-0 text-uppercase fw-bolder"><t t-esc="category.name"/></span>
-        </div>
-        <div class="flex-grow-1"/>
-        <div class="d-flex me-3">
-            <i t-if="category.canView" t-attf-class="fa fa-cog {{ hover_class }}" title="View or join channels" t-on-click="() => this.openCategory(category)" role="img"/>
-            <i t-if="category.canAdd and category.isOpen" class="o-mail-DiscussCategory-add" t-attf-class="fa fa-plus {{ hover_class }} ms-1" t-on-click="() => this.addToCategory(category)" t-att-title="category.addTitle" role="img"/>
-        </div>
-        <div t-if="!category.isOpen and threadService.getDiscussCategoryCounter(category.id) > 0" class="o-mail-DiscussSidebar-badge badge rounded-pill me-3 o-discuss-badge fw-bold">
-            <t t-esc="threadService.getDiscussCategoryCounter(category.id)"/>
-        </div>
-    </div>
-    <t t-if="category.isOpen">
-        <t t-foreach="filteredThreads(category)" t-as="threadLocalId" t-key="threadLocalId" t-call="mail.DiscussCategoryItem">
-            <t t-set="thread" t-value="store.threads[threadLocalId]"/>
-        </t>
-    </t>
-    <t t-elif="category.threads.includes(store.discuss.threadLocalId)" t-call="mail.DiscussCategoryItem">
-        <t t-set="threadLocalId" t-value="store.discuss.threadLocalId"/>
-        <t t-set="thread" t-value="store.threads[threadLocalId]"/>
-    </t>
-</t>
-
-<t t-name="mail.DiscussCategoryItem" owl="1">
-    <t t-set="counter" t-value="threadService.getCounter(thread)"/>
-    <button class="o-mail-DiscussCategoryItem o-mail-DiscussSidebar-item btn btn-secondary d-flex align-items-center w-100 px-0 py-2 border-0 rounded-0 text-reset"
-        t-att-class="{
-            'o-bg-inherit': threadLocalId !== store.discuss.threadLocalId,
-            'o-active': threadLocalId === store.discuss.threadLocalId,
-            'o-unread': thread.message_unread_counter > 0,
-        }"
-        t-on-click="(ev) => this.openThread(ev, thread)"
-    >
-        <div class="o-bg-inherit position-relative d-flex ms-4 flex-shrink-0" style="width:30px;height:30px">
-            <img class="w-100 h-100 rounded" t-att-src="thread.imgUrl" alt="Thread Image"/>
-            <ThreadIcon t-if="thread.type === 'chat' or (thread.type === 'channel' and !thread.authorizedGroupFullName)" thread="thread" size="'small'" className="'o-mail-DiscussCategoryItem-threadIcon position-absolute bottom-0 end-0 p-1 me-n1 mb-n1 d-flex align-items-center justify-content-center rounded-circle o-bg-inherit'"/>
-        </div>
-        <span class="ms-3 me-2 text-truncate" t-att-class="{ 'o-item-unread fw-bolder': thread.message_unread_counter > 0 }">
-            <t t-esc="thread.displayName"/>
-        </span>
-        <div class="flex-grow-1"/>
-        <div class="o-mail-DiscussCategoryItem-commands d-none ms-1 me-3">
-            <i t-if="thread.type === 'channel'" t-attf-class="fa fa-cog {{ hover_class }}" title="Channel settings" t-on-click.stop="() => this.openSettings(thread)" role="img"/>
-            <div t-if="threadService.canLeave(thread)" class="fa fa-times ms-1" t-attf-class="{{ hover_class }}"
-                t-on-click.stop="() => this.leaveChannel(thread)" title="Leave this channel" role="img"/>
-            <div t-if="threadService.canUnpin(thread)" t-attf-class="fa fa-times ms-1 {{ hover_class }}" t-on-click.stop="() => threadService.unpin(thread)" title="Unpin Conversation" role="img"/>
-        </div>
-        <div t-if="Object.keys(thread.rtcSessions).length > 0" class="fa fa-volume-up ms-1 me-3" t-att-class="{ 'text-danger': rtc.state.channel?.id === thread.id }"/>
-        <div t-if="counter > 0">
-            <span t-attf-class="o-mail-DiscussSidebar-badge badge rounded-pill o-discuss-badge ms-1 me-3 fw-bold" t-esc="counter"/>
-        </div>
-    </button>
-</t>
-</templates>
diff --git a/addons/mail/static/src/discuss/call/web/discuss_patch.js b/addons/mail/static/src/discuss/call/web/discuss_patch.js
index 6073289efbe..792fc3abd62 100644
--- a/addons/mail/static/src/discuss/call/web/discuss_patch.js
+++ b/addons/mail/static/src/discuss/call/web/discuss_patch.js
@@ -1,25 +1,27 @@
 /* @odoo-module */
 
 import { Discuss } from "@mail/core/common/discuss";
-import { useEffect } from "@odoo/owl";
+import { useChildSubEnv, useEffect, useState } from "@odoo/owl";
 
 import { patch } from "@web/core/utils/patch";
 
 patch(Discuss.prototype, "discuss/call/web", {
     setup(...args) {
         this._super(...args);
-        Object.assign(this.state, { openInviteButton: 0 });
+        const state = useState({ openInviteButton: 0 });
+        useChildSubEnv({
+            onStartMeeting: () => {
+                state.openInviteButton++;
+            },
+        });
         useEffect(
             () => {
-                if (this.state.openInviteButton === 0) {
+                if (state.openInviteButton === 0) {
                     return;
                 }
                 this.threadActions.actions.find((action) => action.id === "add-users")?.onSelect();
             },
-            () => [this.state.openInviteButton]
+            () => [state.openInviteButton]
         );
     },
-    onStartMeeting() {
-        this.state.openInviteButton++;
-    },
 });
diff --git a/addons/mail/static/src/discuss/call/web/discuss_patch.xml b/addons/mail/static/src/discuss/call/web/discuss_patch.xml
deleted file mode 100644
index 1c51126aca2..00000000000
--- a/addons/mail/static/src/discuss/call/web/discuss_patch.xml
+++ /dev/null
@@ -1,8 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<templates xml:space="preserve">
-    <t t-inherit="mail.Discuss" t-inherit-mode="extension" owl="1">
-        <xpath expr="//Sidebar" position="attributes">
-            <attribute name="onStartMeeting.bind">onStartMeeting</attribute>
-        </t>
-    </t>
-</templates>
diff --git a/addons/mail/static/src/discuss/call/web/discuss_sidebar_call_indicator.js b/addons/mail/static/src/discuss/call/web/discuss_sidebar_call_indicator.js
new file mode 100644
index 00000000000..5f2906aac70
--- /dev/null
+++ b/addons/mail/static/src/discuss/call/web/discuss_sidebar_call_indicator.js
@@ -0,0 +1,24 @@
+/* @odoo-module */
+
+import { Thread } from "@mail/core/common/thread_model";
+import { useRtc } from "@mail/discuss/call/common/rtc_hook";
+import { discussSidebarChannelIndicatorsRegistry } from "@mail/discuss/core/web/discuss_sidebar_categories";
+
+import { Component } from "@odoo/owl";
+
+/**
+ * @typedef {Object} Props
+ * @property {import("@mail/core/common/thread_model").Thread} thread
+ * @extends {Component<Props, Env>}
+ */
+export class DiscussSidebarCallIndicator extends Component {
+    static template = "mail.DiscussSidebarCallIndicator";
+    static props = { thread: { type: Thread } };
+    static components = {};
+
+    setup() {
+        this.rtc = useRtc();
+    }
+}
+
+discussSidebarChannelIndicatorsRegistry.add("call-indicator", DiscussSidebarCallIndicator);
diff --git a/addons/mail/static/src/discuss/call/web/discuss_sidebar_call_indicator.xml b/addons/mail/static/src/discuss/call/web/discuss_sidebar_call_indicator.xml
new file mode 100644
index 00000000000..c7900901ae2
--- /dev/null
+++ b/addons/mail/static/src/discuss/call/web/discuss_sidebar_call_indicator.xml
@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<templates xml:space="preserve">
+    <t t-name="mail.DiscussSidebarCallIndicator" owl="1">
+        <div
+            t-if="Object.keys(props.thread.rtcSessions).length > 0"
+            class="fa fa-volume-up ms-1 me-3"
+            t-att-class="{ 'text-danger': rtc.state.channel?.id === props.thread.id }"
+        />
+    </t>
+</templates>
diff --git a/addons/mail/static/src/discuss/call/web/discuss_sidebar_patch.js b/addons/mail/static/src/discuss/call/web/discuss_sidebar_patch.js
deleted file mode 100644
index ca156104401..00000000000
--- a/addons/mail/static/src/discuss/call/web/discuss_sidebar_patch.js
+++ /dev/null
@@ -1,25 +0,0 @@
-/* @odoo-module */
-
-import { Sidebar } from "@mail/core/web/sidebar";
-import { useRtc } from "@mail/discuss/call/common/rtc_hook";
-import { useDiscussCoreCommon } from "@mail/discuss/core/common/discuss_core_common_service";
-
-import { patch } from "@web/core/utils/patch";
-
-Sidebar.props = [...Sidebar.props, "onStartMeeting?"];
-
-patch(Sidebar.prototype, "discuss/call/web", {
-    setup() {
-        this._super(...arguments);
-        this.discussCoreCommonService = useDiscussCoreCommon();
-        this.rtc = useRtc();
-    },
-    async onClickStartMeeting() {
-        const thread = await this.discussCoreCommonService.createGroupChat({
-            default_display_mode: "video_full_screen",
-            partners_to: [this.store.self.id],
-        });
-        this.rtc.toggleCall(thread, { video: true });
-        this.props.onStartMeeting?.();
-    },
-});
diff --git a/addons/mail/static/src/discuss/call/web/discuss_sidebar_patch.xml b/addons/mail/static/src/discuss/call/web/discuss_sidebar_patch.xml
deleted file mode 100644
index ecbd98b6e14..00000000000
--- a/addons/mail/static/src/discuss/call/web/discuss_sidebar_patch.xml
+++ /dev/null
@@ -1,13 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<templates xml:space="preserve">
-    <t t-inherit="mail.DiscussSidebar" t-inherit-mode="extension" owl="1">
-        <xpath expr="//*[@t-ref='mailboxes']" position="before">
-            <div class="d-flex justify-content-center">
-                <button t-on-click="onClickStartMeeting" class="btn btn-primary rounded" title="Start a meeting">
-                    Start a meeting
-                </button>
-            </div>
-            <hr class="w-100 opacity-0"/>
-        </xpath>
-    </t>
-</templates>
diff --git a/addons/mail/static/src/discuss/call/web/discuss_sidebar_start_meeting.js b/addons/mail/static/src/discuss/call/web/discuss_sidebar_start_meeting.js
new file mode 100644
index 00000000000..903b535d0f3
--- /dev/null
+++ b/addons/mail/static/src/discuss/call/web/discuss_sidebar_start_meeting.js
@@ -0,0 +1,35 @@
+/* @odoo-module */
+
+import { useStore } from "@mail/core/common/messaging_hook";
+import { discussSidebarItemsRegistry } from "@mail/core/web/discuss_sidebar";
+import { useRtc } from "@mail/discuss/call/common/rtc_hook";
+import { useDiscussCoreCommon } from "@mail/discuss/core/common/discuss_core_common_service";
+
+import { Component } from "@odoo/owl";
+
+/**
+ * @typedef {Object} Props
+ * @extends {Component<Props, Env>}
+ */
+export class DiscussSidebarStartMeeting extends Component {
+    static template = "mail.DiscussSidebarStartMeeting";
+    static props = {};
+    static components = {};
+
+    setup() {
+        this.discussCoreCommonService = useDiscussCoreCommon();
+        this.rtc = useRtc();
+        this.store = useStore();
+    }
+
+    async onClickStartMeeting() {
+        const thread = await this.discussCoreCommonService.createGroupChat({
+            default_display_mode: "video_full_screen",
+            partners_to: [this.store.self.id],
+        });
+        this.rtc.toggleCall(thread, { video: true });
+        this.env.onStartMeeting?.();
+    }
+}
+
+discussSidebarItemsRegistry.add("start-meeting", DiscussSidebarStartMeeting, { sequence: 10 });
diff --git a/addons/mail/static/src/discuss/call/web/discuss_sidebar_start_meeting.xml b/addons/mail/static/src/discuss/call/web/discuss_sidebar_start_meeting.xml
new file mode 100644
index 00000000000..27234448f0c
--- /dev/null
+++ b/addons/mail/static/src/discuss/call/web/discuss_sidebar_start_meeting.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<templates xml:space="preserve">
+    <t t-name="mail.DiscussSidebarStartMeeting" owl="1">
+        <div class="d-flex justify-content-center">
+            <button class="btn btn-primary rounded" t-on-click="onClickStartMeeting">Start a meeting</button>
+        </div>
+        <hr class="w-100 opacity-0"/>
+    </t>
+</templates>
diff --git a/addons/mail/static/src/core/web/sidebar.js b/addons/mail/static/src/discuss/core/web/discuss_sidebar_categories.js
similarity index 73%
rename from addons/mail/static/src/core/web/sidebar.js
rename to addons/mail/static/src/discuss/core/web/discuss_sidebar_categories.js
index df10e8e1f5d..bdd99a2e3ec 100644
--- a/addons/mail/static/src/core/web/sidebar.js
+++ b/addons/mail/static/src/discuss/core/web/discuss_sidebar_categories.js
@@ -1,63 +1,123 @@
 /* @odoo-module */
 
 import { ImStatus } from "@mail/core/common/im_status";
-import { useMessaging, useStore } from "@mail/core/common/messaging_hook";
+import { useStore } from "@mail/core/common/messaging_hook";
 import { ThreadIcon } from "@mail/core/common/thread_icon";
+import { discussSidebarItemsRegistry } from "@mail/core/web/discuss_sidebar";
+import { ChannelSelector } from "@mail/discuss/core/web/channel_selector";
 import { onExternalClick } from "@mail/utils/common/hooks";
-import { markEventHandled } from "@web/core/utils/misc";
 
 import { Component, useState } from "@odoo/owl";
 
 import { ConfirmationDialog } from "@web/core/confirmation_dialog/confirmation_dialog";
 import { _t } from "@web/core/l10n/translation";
+import { registry } from "@web/core/registry";
 import { useService } from "@web/core/utils/hooks";
+import { markEventHandled } from "@web/core/utils/misc";
+
+export const discussSidebarCategoriesRegistry = registry.category(
+    "mail.discuss_sidebar_categories"
+);
+export const discussSidebarChannelIndicatorsRegistry = registry.category(
+    "mail.discuss_sidebar_channel_indicators"
+);
+
+discussSidebarCategoriesRegistry.add(
+    "channels",
+    { value: (store) => store.discuss.channels },
+    { sequence: 10 }
+);
+discussSidebarCategoriesRegistry.add(
+    "chats",
+    { value: (store) => store.discuss.chats },
+    { sequence: 30 }
+);
 
 /**
  * @typedef {Object} Props
  * @extends {Component<Props, Env>}
  */
-export class Sidebar extends Component {
-    static template = "mail.DiscussSidebar";
-    static components = { ThreadIcon, ImStatus };
-    static props = [];
+export class DiscussSidebarCategories extends Component {
+    static template = "mail.DiscussSidebarCategories";
+    static props = {};
+    static components = { ChannelSelector, ImStatus, ThreadIcon };
 
     setup() {
-        this.messaging = useMessaging();
         this.store = useStore();
         /** @type {import("@mail/core/common/thread_service").ThreadService} */
         this.threadService = useState(useService("mail.thread"));
-        this.actionService = useService("action");
-        this.dialogService = useService("dialog");
-        this.userSettings = useService("mail.user_settings");
-        this.orm = useService("orm");
         this.state = useState({
             editing: false,
             quickSearchVal: "",
         });
+        this.actionService = useService("action");
+        this.dialogService = useService("dialog");
+        this.userSettings = useService("mail.user_settings");
+        this.orm = useService("orm");
         onExternalClick("selector", () => {
             this.state.editing = false;
         });
     }
 
-    openThread(ev, thread) {
-        markEventHandled(ev, "sidebar.openThread");
-        this.threadService.setDiscussThread(thread);
+    addToCategory(category) {
+        this.state.editing = category.id;
     }
 
-    async toggleCategory(category) {
-        category.isOpen = !category.isOpen;
-        await this.orm.call(
-            "res.users.settings",
-            "set_res_users_settings",
-            [[this.userSettings.id]],
-            {
-                new_settings: {
-                    [category.serverStateKey]: category.isOpen,
-                },
-            }
+    askConfirmation(body) {
+        return new Promise((resolve) => {
+            this.dialogService.add(ConfirmationDialog, {
+                body: body,
+                confirm: resolve,
+                cancel: () => {},
+            });
+        });
+    }
+
+    get categories() {
+        return discussSidebarCategoriesRegistry.getAll();
+    }
+
+    get channelIndicators() {
+        return discussSidebarChannelIndicatorsRegistry.getAll();
+    }
+
+    filteredThreads(category) {
+        return category.threads.filter((threadLocalId) => {
+            const thread = this.store.threads[threadLocalId];
+            return (
+                (thread.is_pinned || thread.group_based_subscription) &&
+                (!this.state.quickSearchVal || thread.name.includes(this.state.quickSearchVal))
+            );
+        });
+    }
+
+    get hasQuickSearch() {
+        return (
+            Object.values(this.store.threads).filter(
+                (thread) => thread.is_pinned && thread.model === "discuss.channel"
+            ).length > 19
         );
     }
 
+    /**
+     * @param {import("@mail/core/common/thread_model").Thread} thread
+     */
+    async leaveChannel(thread) {
+        if (thread.type !== "group" && thread.isAdmin) {
+            await this.askConfirmation(
+                _t("You are the administrator of this channel. Are you sure you want to leave?")
+            );
+        }
+        if (thread.type === "group") {
+            await this.askConfirmation(
+                _t(
+                    "You are about to leave this group conversation and will no longer have access to it unless you are invited again. Are you sure you want to continue?"
+                )
+            );
+        }
+        this.threadService.leaveChannel(thread);
+    }
+
     openCategory(category) {
         if (category.id === "channels") {
             this.actionService.doAction({
@@ -73,6 +133,9 @@ export class Sidebar extends Component {
         }
     }
 
+    /**
+     * @param {import("@mail/core/common/thread_model").Thread} thread
+     */
     openSettings(thread) {
         if (thread.type === "channel") {
             this.actionService.doAction({
@@ -85,55 +148,32 @@ export class Sidebar extends Component {
         }
     }
 
-    addToCategory(category) {
-        this.state.editing = category.id;
+    /**
+     * @param {MouseEvent} ev
+     * @param {import("@mail/core/common/thread_model").Thread} thread
+     */
+    openThread(ev, thread) {
+        markEventHandled(ev, "sidebar.openThread");
+        this.threadService.setDiscussThread(thread);
     }
 
     stopEditing() {
         this.state.editing = false;
     }
 
-    async leaveChannel(thread) {
-        if (thread.type !== "group" && thread.isAdmin) {
-            await this.askConfirmation(
-                _t("You are the administrator of this channel. Are you sure you want to leave?")
-            );
-        }
-        if (thread.type === "group") {
-            await this.askConfirmation(
-                _t(
-                    "You are about to leave this group conversation and will no longer have access to it unless you are invited again. Are you sure you want to continue?"
-                )
-            );
-        }
-        this.threadService.leaveChannel(thread);
-    }
-
-    askConfirmation(body) {
-        return new Promise((resolve) => {
-            this.dialogService.add(ConfirmationDialog, {
-                body: body,
-                confirm: resolve,
-                cancel: () => {},
-            });
-        });
-    }
-
-    get hasQuickSearch() {
-        return (
-            Object.values(this.store.threads).filter(
-                (thread) => thread.is_pinned && thread.model === "discuss.channel"
-            ).length > 19
+    async toggleCategory(category) {
+        category.isOpen = !category.isOpen;
+        await this.orm.call(
+            "res.users.settings",
+            "set_res_users_settings",
+            [[this.userSettings.id]],
+            {
+                new_settings: {
+                    [category.serverStateKey]: category.isOpen,
+                },
+            }
         );
     }
-
-    filteredThreads(category) {
-        return category.threads.filter((threadLocalId) => {
-            const thread = this.store.threads[threadLocalId];
-            return (
-                (thread.is_pinned || thread.group_based_subscription) &&
-                (!this.state.quickSearchVal || thread.name.includes(this.state.quickSearchVal))
-            );
-        });
-    }
 }
+
+discussSidebarItemsRegistry.add("channels", DiscussSidebarCategories, { sequence: 30 });
diff --git a/addons/mail/static/src/discuss/core/web/discuss_sidebar_categories.scss b/addons/mail/static/src/discuss/core/web/discuss_sidebar_categories.scss
new file mode 100644
index 00000000000..fb0a5f8f929
--- /dev/null
+++ b/addons/mail/static/src/discuss/core/web/discuss_sidebar_categories.scss
@@ -0,0 +1,21 @@
+.o-mail-DiscussSidebar {
+    .o-mail-DiscussSidebarCategory-icon {
+        width: 15px;
+        height: 15px;
+    }
+
+    .o-mail-DiscussSidebarCategory-im-status {
+        transform: scale(0.75);
+    }
+}
+
+.o-mail-DiscussSidebar-item {
+    &:hover .o-mail-DiscussSidebarChannel-commands {
+        display: flex !important;
+    }
+}
+.o-mail-DiscussSidebarChannel-threadIcon {
+    font-size: xx-small;
+    width: 13px;
+    height: 13px;
+}
diff --git a/addons/mail/static/src/discuss/core/web/discuss_sidebar_categories.xml b/addons/mail/static/src/discuss/core/web/discuss_sidebar_categories.xml
new file mode 100644
index 00000000000..9481710fb13
--- /dev/null
+++ b/addons/mail/static/src/discuss/core/web/discuss_sidebar_categories.xml
@@ -0,0 +1,73 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<templates xml:space="preserve">
+    <t t-name="mail.DiscussSidebarCategories" owl="1">
+        <hr class="w-100 opacity-0"/>
+        <input t-if="hasQuickSearch" class="form-control mx-4 mb-2 rounded-3 w-auto" placeholder="Quick search..." t-model="state.quickSearchVal"/>
+        <t t-foreach="categories" t-as="categoryData" t-key="categoryData_index">
+            <t t-if="categoryData.predicate?.(store) ?? true" t-call="mail.DiscussSidebarCategory">
+                <t t-set="category" t-value="categoryData.value(store)"/>
+            </t>
+        </t>
+    </t>
+
+    <t t-name="mail.DiscussSidebarCategory" owl="1">
+        <t t-set="hover_class" t-value="'btn p-0 text-start text-700 opacity-100-hover opacity-75'"/>
+        <div class="o-mail-DiscussSidebarCategory d-flex align-items-center my-1" t-att-class="category.extraClass">
+            <div t-attf-class="d-flex align-items-baseline mx-1 {{ hover_class }}" t-on-click="() => this.toggleCategory(category)">
+                <i class="o-mail-DiscussSidebarCategory-icon small me-1" t-att-class="category.isOpen ? 'oi oi-chevron-down' : 'oi oi-chevron-right'"/>
+                <span class="btn-sm p-0 text-uppercase fw-bolder"><t t-esc="category.name"/></span>
+            </div>
+            <div class="flex-grow-1"/>
+            <div class="d-flex me-3">
+                <i t-if="category.canView" t-attf-class="fa fa-cog {{ hover_class }}" title="View or join channels" t-on-click="() => this.openCategory(category)" role="img"/>
+                <i t-if="category.canAdd and category.isOpen" class="o-mail-DiscussSidebarCategory-add" t-attf-class="fa fa-plus {{ hover_class }} ms-1" t-on-click="() => this.addToCategory(category)" t-att-title="category.addTitle" role="img"/>
+            </div>
+            <div t-if="!category.isOpen and threadService.getDiscussSidebarCategoryCounter(category.id) > 0" class="o-mail-DiscussSidebar-badge badge rounded-pill me-3 o-discuss-badge fw-bold">
+                <t t-esc="threadService.getDiscussSidebarCategoryCounter(category.id)"/>
+            </div>
+        </div>
+        <t t-if="category.isOpen">
+            <div t-if="state.editing === category.id" class="p-2" t-ref="selector">
+                <ChannelSelector category="category" onValidate.bind="stopEditing" autofocus="true"/>
+            </div>
+            <t t-foreach="filteredThreads(category)" t-as="threadLocalId" t-key="threadLocalId" t-call="mail.DiscussSidebarChannel">
+                <t t-set="thread" t-value="store.threads[threadLocalId]"/>
+            </t>
+        </t>
+        <t t-elif="category.threads.includes(store.discuss.threadLocalId)" t-call="mail.DiscussSidebarChannel">
+            <t t-set="threadLocalId" t-value="store.discuss.threadLocalId"/>
+            <t t-set="thread" t-value="store.threads[threadLocalId]"/>
+        </t>
+    </t>
+
+    <t t-name="mail.DiscussSidebarChannel" owl="1">
+        <t t-set="counter" t-value="threadService.getCounter(thread)"/>
+        <button class="o-mail-DiscussSidebarChannel o-mail-DiscussSidebar-item btn btn-secondary d-flex align-items-center w-100 px-0 py-2 border-0 rounded-0 text-reset"
+            t-att-class="{
+                'o-bg-inherit': threadLocalId !== store.discuss.threadLocalId,
+                'o-active': threadLocalId === store.discuss.threadLocalId,
+                'o-unread': thread.message_unread_counter > 0,
+            }"
+            t-on-click="(ev) => this.openThread(ev, thread)"
+        >
+            <div class="o-bg-inherit position-relative d-flex ms-4 flex-shrink-0" style="width:30px;height:30px">
+                <img class="w-100 h-100 rounded" t-att-src="thread.imgUrl" alt="Thread Image"/>
+                <ThreadIcon t-if="thread.type === 'chat' or (thread.type === 'channel' and !thread.authorizedGroupFullName)" thread="thread" size="'small'" className="'o-mail-DiscussSidebarChannel-threadIcon position-absolute bottom-0 end-0 p-1 me-n1 mb-n1 d-flex align-items-center justify-content-center rounded-circle o-bg-inherit'"/>
+            </div>
+            <span class="ms-3 me-2 text-truncate" t-att-class="{ 'o-item-unread fw-bolder': thread.message_unread_counter > 0 }">
+                <t t-esc="thread.displayName"/>
+            </span>
+            <div class="flex-grow-1"/>
+            <div class="o-mail-DiscussSidebarChannel-commands d-none ms-1 me-3">
+                <i t-if="thread.type === 'channel'" t-attf-class="fa fa-cog {{ hover_class }}" title="Channel settings" t-on-click.stop="() => this.openSettings(thread)" role="img"/>
+                <div t-if="threadService.canLeave(thread)" class="fa fa-times ms-1" t-attf-class="{{ hover_class }}"
+                    t-on-click.stop="() => this.leaveChannel(thread)" title="Leave this channel" role="img"/>
+                <div t-if="threadService.canUnpin(thread)" t-attf-class="fa fa-times ms-1 {{ hover_class }}" t-on-click.stop="() => threadService.unpin(thread)" title="Unpin Conversation" role="img"/>
+            </div>
+            <t t-foreach="channelIndicators" t-as="indicator" t-key="indicator_index" t-component="indicator" t-props="{ thread }"/>
+            <div t-if="counter > 0">
+                <span t-attf-class="o-mail-DiscussSidebar-badge badge rounded-pill o-discuss-badge ms-1 me-3 fw-bold" t-esc="counter"/>
+            </div>
+        </button>
+    </t>
+</templates>
diff --git a/addons/mail/static/src/discuss/core/web/discuss_tour.js b/addons/mail/static/src/discuss/core/web/discuss_tour.js
index 7d637ac1111..12fe425e638 100644
--- a/addons/mail/static/src/discuss/core/web/discuss_tour.js
+++ b/addons/mail/static/src/discuss/core/web/discuss_tour.js
@@ -10,7 +10,7 @@ registry.category("web_tour.tours").add("mail_tour", {
     sequence: 80,
     steps: () => [
         {
-            trigger: ".o-mail-DiscussCategory-channel .o-mail-DiscussCategory-add",
+            trigger: ".o-mail-DiscussSidebarCategory-channel .o-mail-DiscussSidebarCategory-add",
             content: Markup(
                 _t(
                     "<p>Channels make it easy to organize information across different topics and groups.</p> <p>Try to <b>create your first channel</b> (e.g. sales, marketing, product XYZ, after work party, etc).</p>"
@@ -81,7 +81,7 @@ registry.category("web_tour.tours").add("mail_tour", {
             position: "bottom",
         },
         {
-            trigger: ".o-mail-DiscussCategory-chat .o-mail-DiscussCategory-add",
+            trigger: ".o-mail-DiscussSidebarCategory-chat .o-mail-DiscussSidebarCategory-add",
             content: Markup(
                 _t(
                     "<p><b>Chat with coworkers</b> in real-time using direct messages.</p><p><i>You might need to invite users from the Settings app first.</i></p>"
diff --git a/addons/mail/static/src/discuss/core/web/sidebar_patch.js b/addons/mail/static/src/discuss/core/web/sidebar_patch.js
deleted file mode 100644
index e5557706815..00000000000
--- a/addons/mail/static/src/discuss/core/web/sidebar_patch.js
+++ /dev/null
@@ -1,6 +0,0 @@
-/* @odoo-module */
-
-import { Sidebar } from "@mail/core/web/sidebar";
-import { ChannelSelector } from "@mail/discuss/core/web/channel_selector";
-
-Object.assign(Sidebar.components, { ChannelSelector });
diff --git a/addons/mail/static/src/discuss/core/web/sidebar_patch.xml b/addons/mail/static/src/discuss/core/web/sidebar_patch.xml
deleted file mode 100644
index ea32f2a19b2..00000000000
--- a/addons/mail/static/src/discuss/core/web/sidebar_patch.xml
+++ /dev/null
@@ -1,10 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<templates xml:space="preserve">
-    <t t-inherit="mail.DiscussCategory" t-inherit-mode="extension" owl="1">
-        <xpath expr="//t[@t-call='mail.DiscussCategoryItem']" position="before">
-            <div t-if="state.editing === category.id" class="p-2" t-ref="selector">
-                <ChannelSelector category="category" onValidate.bind="stopEditing" autofocus="true"/>
-            </div>
-        </xpath>
-    </t>
-</templates>
diff --git a/addons/mail/static/src/js/tours/load_message_order_tour.js b/addons/mail/static/src/js/tours/load_message_order_tour.js
index daf90136dbc..c87d67e0680 100644
--- a/addons/mail/static/src/js/tours/load_message_order_tour.js
+++ b/addons/mail/static/src/js/tours/load_message_order_tour.js
@@ -6,7 +6,7 @@ registry.category("web_tour.tours").add("mail.load_message_order", {
     test: true,
     steps: () => [
         {
-            trigger: ".o-mail-DiscussCategoryItem:contains(MyTestChannel)",
+            trigger: ".o-mail-DiscussSidebarChannel:contains(MyTestChannel)",
             run: "click",
         },
         {
diff --git a/addons/mail/static/tests/composer/composer_tests.js b/addons/mail/static/tests/composer/composer_tests.js
index c85dbd4f3d3..656f30383fd 100644
--- a/addons/mail/static/tests/composer/composer_tests.js
+++ b/addons/mail/static/tests/composer/composer_tests.js
@@ -190,8 +190,8 @@ QUnit.test(
         const textarea = $(".o-mail-Composer-input")[0];
         textarea.setSelectionRange(0, textarea.value.length);
         await nextTick();
-        await click($(".o-mail-DiscussCategoryItem:eq(1)"));
-        await click($(".o-mail-DiscussCategoryItem:eq(0)"));
+        await click($(".o-mail-DiscussSidebarChannel:eq(1)"));
+        await click($(".o-mail-DiscussSidebarChannel:eq(0)"));
         assert.ok(textarea.selectionStart === 0 && textarea.selectionEnd === textarea.value.length);
     }
 );
@@ -478,10 +478,10 @@ QUnit.test("leave command on channel", async (assert) => {
         },
     });
     await openDiscuss(channelId);
-    assert.hasClass($(".o-mail-DiscussCategoryItem:contains(general)"), "o-active");
+    assert.hasClass($(".o-mail-DiscussSidebarChannel:contains(general)"), "o-active");
     await insertText(".o-mail-Composer-input", "/leave");
     await afterNextRender(() => triggerHotkey("Enter"));
-    assert.containsNone($, ".o-mail-DiscussCategoryItem:contains(general)");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel:contains(general)");
     assert.containsOnce($, ".o-mail-Discuss:contains(No conversation selected.)");
     assert.verifySteps(["You unsubscribed from general."]);
 });
@@ -525,10 +525,10 @@ QUnit.test("leave command on chat", async (assert) => {
         },
     });
     await openDiscuss(channelId);
-    assert.hasClass($(".o-mail-DiscussCategoryItem:contains(Chuck Norris)"), "o-active");
+    assert.hasClass($(".o-mail-DiscussSidebarChannel:contains(Chuck Norris)"), "o-active");
     await insertText(".o-mail-Composer-input", "/leave");
     await afterNextRender(() => triggerHotkey("Enter"));
-    assert.containsNone($, ".o-mail-DiscussCategoryItem:contains(Chuck Norris)");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel:contains(Chuck Norris)");
     assert.containsOnce($, ".o-mail-Discuss:contains(No conversation selected.)");
     assert.verifySteps(["You unpinned your conversation with Chuck Norris"]);
 });
diff --git a/addons/mail/static/tests/crosstab/crosstab_tests.js b/addons/mail/static/tests/crosstab/crosstab_tests.js
index 7bf7fa2124a..593a1b4495e 100644
--- a/addons/mail/static/tests/crosstab/crosstab_tests.js
+++ b/addons/mail/static/tests/crosstab/crosstab_tests.js
@@ -66,7 +66,7 @@ QUnit.test("Thread rename", async (assert) => {
     await tab1.insertText(".o-mail-Discuss-threadName", "Sales", { replace: true });
     await afterNextRender(() => triggerHotkey("Enter"));
     assert.containsOnce(tab2.target, ".o-mail-Discuss-threadName[title='Sales']");
-    assert.containsOnce(tab2.target, ".o-mail-DiscussCategoryItem:contains(Sales)");
+    assert.containsOnce(tab2.target, ".o-mail-DiscussSidebarChannel:contains(Sales)");
 });
 
 QUnit.test("Thread description update", async (assert) => {
@@ -118,7 +118,7 @@ QUnit.test("Channel subscription is renewed when channel is left", async (assert
         },
     });
     await openDiscuss();
-    await click(".o-mail-DiscussCategoryItem .btn[title='Leave this channel']");
+    await click(".o-mail-DiscussSidebarChannel .btn[title='Leave this channel']");
     assert.verifySteps(["update-channels"]);
 });
 
diff --git a/addons/mail/static/tests/discuss/call/call_tests.js b/addons/mail/static/tests/discuss/call/call_tests.js
index 6e9d791025c..21428a16f56 100644
--- a/addons/mail/static/tests/discuss/call/call_tests.js
+++ b/addons/mail/static/tests/discuss/call/call_tests.js
@@ -207,6 +207,6 @@ QUnit.test("Create a direct message channel when clicking on start a meeting", a
     const { openDiscuss } = await start();
     await openDiscuss();
     await click("button:contains(Start a meeting)");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(Mitchell Admin)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(Mitchell Admin)");
     assert.containsOnce($, ".o-discuss-Call");
 });
diff --git a/addons/mail/static/tests/discuss/call/web/call_tests.js b/addons/mail/static/tests/discuss/call/web/call_tests.js
index 0cad45aa2de..70ec3acb1d5 100644
--- a/addons/mail/static/tests/discuss/call/web/call_tests.js
+++ b/addons/mail/static/tests/discuss/call/web/call_tests.js
@@ -12,7 +12,7 @@ QUnit.test("no default rtc after joining a chat conversation", async (assert) =>
     pyEnv["res.users"].create({ partner_id: partnerId });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsNone($, ".o-mail-DiscussCategoryItem");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel");
 
     await click(".o-mail-DiscussSidebar i[title='Start a conversation']");
     await afterNextRender(() =>
@@ -22,7 +22,7 @@ QUnit.test("no default rtc after joining a chat conversation", async (assert) =>
     await triggerEvent(document.body, ".o-discuss-ChannelSelector input", "keydown", {
         key: "Enter",
     });
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel");
     assert.containsNone($, ".o-mail-Discuss-content .o-mail-Message");
     assert.containsNone($, ".o-discuss-Call");
 });
@@ -36,7 +36,7 @@ QUnit.test("no default rtc after joining a group conversation", async (assert) =
     pyEnv["res.users"].create([{ partner_id: partnerId_1 }, { partner_id: partnerId_2 }]);
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsNone($, ".o-mail-DiscussCategoryItem");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel");
     await click(".o-mail-DiscussSidebar i[title='Start a conversation']");
     await afterNextRender(() =>
         editInput(document.body, ".o-discuss-ChannelSelector input", "mario")
@@ -49,7 +49,7 @@ QUnit.test("no default rtc after joining a group conversation", async (assert) =
     await triggerEvent(document.body, ".o-discuss-ChannelSelector input", "keydown", {
         key: "Enter",
     });
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel");
     assert.containsNone($, ".o-mail-Discuss-content .o-mail-Message");
     assert.containsNone($, ".o-discuss-Call");
 });
diff --git a/addons/mail/static/tests/discuss/core/suggestion_tests.js b/addons/mail/static/tests/discuss/core/suggestion_tests.js
index 837b6ce5c32..84cb5c91cae 100644
--- a/addons/mail/static/tests/discuss/core/suggestion_tests.js
+++ b/addons/mail/static/tests/discuss/core/suggestion_tests.js
@@ -118,11 +118,11 @@ QUnit.test("Sort partner suggestions by recent chats", async (assert) => {
     ]);
     const { openDiscuss } = await start();
     await openDiscuss();
-    await click(".o-mail-DiscussCategoryItem:contains('User 2')");
+    await click(".o-mail-DiscussSidebarChannel:contains('User 2')");
     await insertText(".o-mail-Composer-input", "This is a test");
     await click(".o-mail-Composer-send:not(:disabled)");
     assert.containsOnce($, ".o-mail-Message:contains('This is a test')");
-    await click(".o-mail-DiscussCategoryItem:contains('General')");
+    await click(".o-mail-DiscussSidebarChannel:contains('General')");
     await insertText(".o-mail-Composer-input", "@");
     await insertText(".o-mail-Composer-input", "User");
     assert.containsN($, ".o-mail-Composer-suggestion", 3);
diff --git a/addons/mail/static/tests/discuss/core/web/discuss_tests.js b/addons/mail/static/tests/discuss/core/web/discuss_tests.js
index bc9cb61e1c1..d4600bacc6b 100644
--- a/addons/mail/static/tests/discuss/core/web/discuss_tests.js
+++ b/addons/mail/static/tests/discuss/core/web/discuss_tests.js
@@ -29,14 +29,14 @@ QUnit.test("can create a new channel [REQUIRE FOCUS]", async (assert) => {
         },
     });
     await openDiscuss();
-    assert.containsNone($, ".o-mail-DiscussCategoryItem");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel");
 
     await click(".o-mail-DiscussSidebar i[title='Add or join a channel']");
     await afterNextRender(() =>
         editInput(document.body, ".o-discuss-ChannelSelector input", "abc")
     );
     await click(".o-discuss-ChannelSelector-suggestion");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel");
     assert.containsNone($, ".o-mail-Discuss-content .o-mail-Message");
     assert.verifySteps([
         "/mail/init_messaging",
@@ -56,7 +56,7 @@ QUnit.test(
         pyEnv["res.users"].create({ partner_id: partnerId });
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.containsNone($, ".o-mail-DiscussCategoryItem");
+        assert.containsNone($, ".o-mail-DiscussSidebarChannel");
 
         await click("i[title='Start a conversation']");
         await afterNextRender(() =>
@@ -64,7 +64,7 @@ QUnit.test(
         );
         await click(".o-discuss-ChannelSelector-suggestion");
         assert.containsOnce($, ".o-discuss-ChannelSelector span[title='Mario']");
-        assert.containsNone($, ".o-mail-DiscussCategoryItem");
+        assert.containsNone($, ".o-mail-DiscussSidebarChannel");
 
         await triggerEvent(document.body, ".o-discuss-ChannelSelector input", "keydown", {
             key: "Backspace",
@@ -78,7 +78,7 @@ QUnit.test(
             key: "Enter",
         });
         assert.containsOnce($, ".o-discuss-ChannelSelector span[title='Mario']");
-        assert.containsNone($, ".o-mail-DiscussCategoryItem");
+        assert.containsNone($, ".o-mail-DiscussSidebarChannel");
     }
 );
 
@@ -101,7 +101,7 @@ QUnit.test("can join a chat conversation", async (assert) => {
         },
     });
     await openDiscuss();
-    assert.containsNone($, ".o-mail-DiscussCategoryItem");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel");
 
     await click(".o-mail-DiscussSidebar i[title='Start a conversation']");
     await afterNextRender(() =>
@@ -111,7 +111,7 @@ QUnit.test("can join a chat conversation", async (assert) => {
     await triggerEvent(document.body, ".o-discuss-ChannelSelector input", "keydown", {
         key: "Enter",
     });
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel");
     assert.containsNone($, ".o-mail-Message");
     assert.verifySteps([
         "/mail/init_messaging",
@@ -131,7 +131,7 @@ QUnit.test("can create a group chat conversation", async (assert) => {
     pyEnv["res.users"].create([{ partner_id: partnerId_1 }, { partner_id: partnerId_2 }]);
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsNone($, ".o-mail-DiscussCategoryItem");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel");
     await click(".o-mail-DiscussSidebar i[title='Start a conversation']");
     await insertText(".o-discuss-ChannelSelector input", "Mario");
     await click(".o-discuss-ChannelSelector-suggestion");
@@ -140,7 +140,7 @@ QUnit.test("can create a group chat conversation", async (assert) => {
     await triggerEvent(document.body, ".o-discuss-ChannelSelector input", "keydown", {
         key: "Enter",
     });
-    assert.containsN($, ".o-mail-DiscussCategoryItem", 1);
+    assert.containsN($, ".o-mail-DiscussSidebarChannel", 1);
     assert.containsNone($, ".o-mail-Message");
 });
 
@@ -150,7 +150,7 @@ QUnit.test("should create DM chat when adding self and another user", async (ass
     pyEnv["res.users"].create({ partner_id });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsNone($, ".o-mail-DiscussCategoryItem");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel");
     await click(".o-mail-DiscussSidebar i[title='Start a conversation']");
     await insertText(".o-discuss-ChannelSelector input", "Mi"); // Mitchell Admin
     await click(".o-discuss-ChannelSelector-suggestion");
@@ -159,7 +159,7 @@ QUnit.test("should create DM chat when adding self and another user", async (ass
     await triggerEvent(document.body, ".o-discuss-ChannelSelector input", "keydown", {
         key: "Enter",
     });
-    assert.strictEqual($(".o-mail-DiscussCategoryItem:contains(Mario)").text(), "Mario");
+    assert.strictEqual($(".o-mail-DiscussSidebarChannel:contains(Mario)").text(), "Mario");
 });
 
 QUnit.test("chat search should display no result when no matches found", async (assert) => {
@@ -178,7 +178,7 @@ QUnit.test(
         pyEnv["res.users"].create({ partner_id: partnerId });
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.containsNone($, ".o-mail-DiscussCategoryItem");
+        assert.containsNone($, ".o-mail-DiscussSidebarChannel");
         await click(".o-mail-DiscussSidebar i[title='Start a conversation']");
         await insertText(".o-discuss-ChannelSelector", "Panda");
         assert.containsOnce($, ".o-discuss-ChannelSelector-suggestion");
@@ -190,13 +190,16 @@ QUnit.test(
 QUnit.test("sidebar: add channel", async (assert) => {
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategory-channel .o-mail-DiscussCategory-add");
+    assert.containsOnce(
+        $,
+        ".o-mail-DiscussSidebarCategory-channel .o-mail-DiscussSidebarCategory-add"
+    );
     assert.hasAttrValue(
-        $(".o-mail-DiscussCategory-channel .o-mail-DiscussCategory-add")[0],
+        $(".o-mail-DiscussSidebarCategory-channel .o-mail-DiscussSidebarCategory-add")[0],
         "title",
         "Add or join a channel"
     );
-    await click(".o-mail-DiscussCategory-channel .o-mail-DiscussCategory-add");
+    await click(".o-mail-DiscussSidebarCategory-channel .o-mail-DiscussSidebarCategory-add");
     assert.containsOnce($, ".o-discuss-ChannelSelector");
     assert.containsOnce($, ".o-discuss-ChannelSelector input[placeholder='Add or join a channel']");
 });
@@ -209,10 +212,10 @@ QUnit.test("Chat is added to discuss on other tab that the one that joined", asy
     const tab2 = await start({ asTab: true });
     await tab1.openDiscuss();
     await tab2.openDiscuss();
-    await tab1.click(".o-mail-DiscussCategory-chat .o-mail-DiscussCategory-add");
+    await tab1.click(".o-mail-DiscussSidebarCategory-chat .o-mail-DiscussSidebarCategory-add");
     await tab1.insertText(".o-discuss-ChannelSelector input", "Jer");
     await tab1.click(".o-discuss-ChannelSelector-suggestion");
     await afterNextRender(() => triggerHotkey("Enter"));
-    assert.containsOnce(tab1.target, ".o-mail-DiscussCategoryItem:contains(Jerry Golay)");
-    assert.containsOnce(tab2.target, ".o-mail-DiscussCategoryItem:contains(Jerry Golay)");
+    assert.containsOnce(tab1.target, ".o-mail-DiscussSidebarChannel:contains(Jerry Golay)");
+    assert.containsOnce(tab2.target, ".o-mail-DiscussSidebarChannel:contains(Jerry Golay)");
 });
diff --git a/addons/mail/static/tests/discuss/core/web/sidebar_tests.js b/addons/mail/static/tests/discuss/core/web/sidebar_tests.js
index a7a80ca6b63..4659625eeca 100644
--- a/addons/mail/static/tests/discuss/core/web/sidebar_tests.js
+++ b/addons/mail/static/tests/discuss/core/web/sidebar_tests.js
@@ -30,7 +30,7 @@ QUnit.test("sidebar find shows channels matching search term", async (assert) =>
         },
     });
     await openDiscuss();
-    await click(".o-mail-DiscussCategory-add");
+    await click(".o-mail-DiscussSidebarCategory-add");
     await insertText(".o-discuss-ChannelSelector input", "test");
     await def;
     await nextAnimationFrame(); // ensures search_read rpc is rendered.
@@ -60,7 +60,7 @@ QUnit.test(
             },
         });
         await openDiscuss();
-        await click(".o-mail-DiscussCategory-add");
+        await click(".o-mail-DiscussSidebarCategory-add");
         await insertText(".o-discuss-ChannelSelector input", "test");
         await def;
         await nextAnimationFrame(); // ensures search_read rpc is rendered.
diff --git a/addons/mail/static/tests/discuss/typing/typing_tests.js b/addons/mail/static/tests/discuss/typing/typing_tests.js
index b07df9da2c8..06a2cc4abcf 100644
--- a/addons/mail/static/tests/discuss/typing/typing_tests.js
+++ b/addons/mail/static/tests/discuss/typing/typing_tests.js
@@ -337,7 +337,10 @@ QUnit.test("chat: correspondent is typing", async (assert) => {
     });
     const { env, openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($(".o-mail-DiscussCategoryItem"), ".o-mail-DiscussCategoryItem-threadIcon");
+    assert.containsOnce(
+        $(".o-mail-DiscussSidebarChannel"),
+        ".o-mail-DiscussSidebarChannel-threadIcon"
+    );
     assert.containsOnce($, ".fa-circle.text-success");
 
     // simulate receive typing notification from demo "is typing"
diff --git a/addons/mail/static/tests/discuss_app/discuss_tests.js b/addons/mail/static/tests/discuss_app/discuss_tests.js
index 8980b14503d..9ff396dfc35 100644
--- a/addons/mail/static/tests/discuss_app/discuss_tests.js
+++ b/addons/mail/static/tests/discuss_app/discuss_tests.js
@@ -240,10 +240,10 @@ QUnit.test("sidebar: chat im_status rendering", async (assert) => {
     ]);
     const { openDiscuss } = await start({ hasTimeControl: true });
     await openDiscuss();
-    assert.containsN($, ".o-mail-DiscussCategoryItem-threadIcon", 3);
-    const chat1 = $(".o-mail-DiscussCategoryItem")[0];
-    const chat2 = $(".o-mail-DiscussCategoryItem")[1];
-    const chat3 = $(".o-mail-DiscussCategoryItem")[2];
+    assert.containsN($, ".o-mail-DiscussSidebarChannel-threadIcon", 3);
+    const chat1 = $(".o-mail-DiscussSidebarChannel")[0];
+    const chat2 = $(".o-mail-DiscussSidebarChannel")[1];
+    const chat3 = $(".o-mail-DiscussSidebarChannel")[2];
     assert.strictEqual(chat1.textContent, "Partner1");
     assert.strictEqual(chat2.textContent, "Partner2");
     assert.strictEqual(chat3.textContent, "Partner3");
@@ -313,7 +313,7 @@ QUnit.test("sidebar: chat custom name", async (assert) => {
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.strictEqual($(".o-mail-DiscussCategoryItem span").text(), "Marc");
+    assert.strictEqual($(".o-mail-DiscussSidebarChannel span").text(), "Marc");
 });
 
 QUnit.test("reply to message from inbox (message linked to document)", async (assert) => {
@@ -473,11 +473,11 @@ QUnit.test("basic rendering: sidebar", async (assert) => {
     assert.containsOnce($, ".o-mail-DiscussSidebar button:contains(Inbox)");
     assert.containsOnce($, ".o-mail-DiscussSidebar button:contains(Starred)");
     assert.containsOnce($, ".o-mail-DiscussSidebar button:contains(History)");
-    assert.containsN($, ".o-mail-DiscussCategory", 2);
-    assert.containsOnce($, ".o-mail-DiscussCategory-channel");
-    assert.containsOnce($, ".o-mail-DiscussCategory-chat");
-    assert.strictEqual($(".o-mail-DiscussCategory-channel").text(), "Channels");
-    assert.strictEqual($(".o-mail-DiscussCategory-chat").text(), "Direct messages");
+    assert.containsN($, ".o-mail-DiscussSidebarCategory", 2);
+    assert.containsOnce($, ".o-mail-DiscussSidebarCategory-channel");
+    assert.containsOnce($, ".o-mail-DiscussSidebarCategory-chat");
+    assert.strictEqual($(".o-mail-DiscussSidebarCategory-channel").text(), "Channels");
+    assert.strictEqual($(".o-mail-DiscussSidebarCategory-chat").text(), "Direct messages");
 });
 
 QUnit.test("sidebar: Inbox should have icon", async (assert) => {
@@ -511,20 +511,23 @@ QUnit.test("sidebar: basic channel rendering", async (assert) => {
     pyEnv["discuss.channel"].create({ name: "General" });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem");
-    assert.strictEqual($(".o-mail-DiscussCategoryItem").text(), "General");
-    assert.containsOnce($(".o-mail-DiscussCategoryItem"), "img[data-alt='Thread Image']");
-    assert.containsOnce($(".o-mail-DiscussCategoryItem"), ".o-mail-DiscussCategoryItem-commands");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel");
+    assert.strictEqual($(".o-mail-DiscussSidebarChannel").text(), "General");
+    assert.containsOnce($(".o-mail-DiscussSidebarChannel"), "img[data-alt='Thread Image']");
+    assert.containsOnce(
+        $(".o-mail-DiscussSidebarChannel"),
+        ".o-mail-DiscussSidebarChannel-commands"
+    );
     assert.hasClass(
-        $(".o-mail-DiscussCategoryItem .o-mail-DiscussCategoryItem-commands"),
+        $(".o-mail-DiscussSidebarChannel .o-mail-DiscussSidebarChannel-commands"),
         "d-none"
     );
     assert.containsOnce(
-        $(".o-mail-DiscussCategoryItem .o-mail-DiscussCategoryItem-commands"),
+        $(".o-mail-DiscussSidebarChannel .o-mail-DiscussSidebarChannel-commands"),
         "i[title='Channel settings']"
     );
     assert.containsOnce(
-        $(".o-mail-DiscussCategoryItem .o-mail-DiscussCategoryItem-commands"),
+        $(".o-mail-DiscussSidebarChannel .o-mail-DiscussSidebarChannel-commands"),
         "div[title='Leave this channel']"
     );
 });
@@ -534,10 +537,10 @@ QUnit.test("channel become active", async (assert) => {
     pyEnv["discuss.channel"].create({ name: "General" });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem");
-    assert.containsNone($, ".o-mail-DiscussCategoryItem.o-active");
-    await click(".o-mail-DiscussCategoryItem");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem.o-active");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel.o-active");
+    await click(".o-mail-DiscussSidebarChannel");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel.o-active");
 });
 
 QUnit.test("channel become active - show composer in discuss content", async (assert) => {
@@ -545,7 +548,7 @@ QUnit.test("channel become active - show composer in discuss content", async (as
     pyEnv["discuss.channel"].create({ name: "General" });
     const { openDiscuss } = await start();
     await openDiscuss();
-    await click(".o-mail-DiscussCategoryItem");
+    await click(".o-mail-DiscussSidebarChannel");
     assert.containsOnce($, ".o-mail-Thread");
     assert.containsOnce($, ".o-mail-Composer");
 });
@@ -565,8 +568,8 @@ QUnit.test("sidebar: channel rendering with needaction counter", async (assert)
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(general)");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(general) .badge:contains(1)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(general)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(general) .badge:contains(1)");
 });
 
 QUnit.test("sidebar: chat rendering with unread counter", async (assert) => {
@@ -579,10 +582,10 @@ QUnit.test("sidebar: chat rendering with unread counter", async (assert) => {
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem .badge:contains(100)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel .badge:contains(100)");
     assert.containsNone(
         $,
-        ".o-mail-DiscussCategoryItem .o-mail-DiscussCategoryItem-commands:contains(Unpin Conversation)"
+        ".o-mail-DiscussSidebarChannel .o-mail-DiscussSidebarChannel-commands:contains(Unpin Conversation)"
     );
 });
 
@@ -621,7 +624,7 @@ QUnit.test("basic top bar rendering", async (assert) => {
     assert.isVisible($unstarAll);
     assert.ok($unstarAll[0].disabled);
 
-    await click(".o-mail-DiscussCategoryItem:contains(General)");
+    await click(".o-mail-DiscussSidebarChannel:contains(General)");
     assert.strictEqual($(".o-mail-Discuss-threadName").val(), "General");
     assert.isVisible($(".o-mail-Discuss-header button[title='Add Users']"));
 });
@@ -927,19 +930,19 @@ QUnit.test("auto-focus composer on opening thread", async (assert) => {
     await openDiscuss();
     assert.containsOnce($, "button:contains(Inbox)");
     assert.hasClass($("button:contains(Inbox)"), "o-active");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(General)");
-    assert.doesNotHaveClass($(".o-mail-DiscussCategoryItem:contains(General)"), "o-active");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(Demo User)");
-    assert.doesNotHaveClass($(".o-mail-DiscussCategoryItem:contains(Demo User)"), "o-active");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(General)");
+    assert.doesNotHaveClass($(".o-mail-DiscussSidebarChannel:contains(General)"), "o-active");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(Demo User)");
+    assert.doesNotHaveClass($(".o-mail-DiscussSidebarChannel:contains(Demo User)"), "o-active");
     assert.containsNone($, ".o-mail-Composer");
 
-    await click(".o-mail-DiscussCategoryItem:contains(General)");
-    assert.hasClass($(".o-mail-DiscussCategoryItem:contains(General)"), "o-active");
+    await click(".o-mail-DiscussSidebarChannel:contains(General)");
+    assert.hasClass($(".o-mail-DiscussSidebarChannel:contains(General)"), "o-active");
     assert.containsOnce($, ".o-mail-Composer");
     assert.strictEqual(document.activeElement, $(".o-mail-Composer-input")[0]);
 
-    await click(".o-mail-DiscussCategoryItem:contains(Demo User)");
-    assert.hasClass($(".o-mail-DiscussCategoryItem:contains(Demo User)"), "o-active");
+    await click(".o-mail-DiscussSidebarChannel:contains(Demo User)");
+    assert.hasClass($(".o-mail-DiscussSidebarChannel:contains(Demo User)"), "o-active");
     assert.containsOnce($, ".o-mail-Composer");
     assert.strictEqual(document.activeElement, $(".o-mail-Composer-input")[0]);
 });
@@ -1110,7 +1113,7 @@ QUnit.test("should auto-pin chat when receiving a new DM", async (assert) => {
     });
     const { env, openDiscuss } = await start();
     await openDiscuss();
-    assert.containsNone($, ".o-mail-DiscussCategoryItem:contains(Demo)");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel:contains(Demo)");
 
     // simulate receiving the first message on channel 11
     await afterNextRender(() =>
@@ -1121,7 +1124,7 @@ QUnit.test("should auto-pin chat when receiving a new DM", async (assert) => {
             thread_model: "discuss.channel",
         })
     );
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(Demo)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(Demo)");
 });
 
 QUnit.test("'Add Users' button should be displayed in the topbar of channels", async (assert) => {
@@ -1254,18 +1257,18 @@ QUnit.test(
         ]);
         const { openDiscuss } = await start();
         await openDiscuss();
-        await click(".o-mail-DiscussCategoryItem:contains('Michel Online')");
+        await click(".o-mail-DiscussSidebarChannel:contains('Michel Online')");
         assert.containsOnce($, ".o-mail-Discuss-header .o-mail-ImStatus [title='Online']");
-        await click(".o-mail-DiscussCategoryItem:contains('Jacqueline Offline')");
+        await click(".o-mail-DiscussSidebarChannel:contains('Jacqueline Offline')");
         assert.containsOnce($, ".o-mail-Discuss-header .o-mail-ImStatus [title='Offline']");
-        await click(".o-mail-DiscussCategoryItem:contains('Nabuchodonosor Idle')");
+        await click(".o-mail-DiscussSidebarChannel:contains('Nabuchodonosor Idle')");
         assert.containsOnce($, ".o-mail-Discuss-header .o-mail-ImStatus [title='Idle']");
-        await click(".o-mail-DiscussCategoryItem:contains('Robert Fired')");
+        await click(".o-mail-DiscussSidebarChannel:contains('Robert Fired')");
         assert.containsOnce(
             $,
             ".o-mail-Discuss-header .o-mail-ImStatus [title='No IM status available']"
         );
-        await click(".o-mail-DiscussCategoryItem:contains('OdooBot')");
+        await click(".o-mail-DiscussSidebarChannel:contains('OdooBot')");
         assert.containsOnce($, ".o-mail-Discuss-header .o-mail-ImStatus [title='Bot']");
     }
 );
@@ -1338,14 +1341,14 @@ QUnit.test("Channel is added to discuss after invitation", async (assert) => {
         },
     });
     await openDiscuss();
-    assert.containsNone($, ".o-mail-DiscussCategoryItem:contains(General)");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel:contains(General)");
     await afterNextRender(() => {
         env.services.orm.call("discuss.channel", "add_members", [[channelId]], {
             partner_ids: [pyEnv.currentPartnerId],
             context: { mockedUserId: userId },
         });
     });
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(General)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(General)");
     assert.verifySteps(["You have been invited to #General"]);
 });
 
@@ -1828,7 +1831,9 @@ QUnit.test("Message shows up even if channel data is incomplete", async (assert)
                 thread_model: "discuss.channel",
             })
     );
-    await click(".o-mail-DiscussCategory-chat + .o-mail-DiscussCategoryItem:contains(Albert)");
+    await click(
+        ".o-mail-DiscussSidebarCategory-chat + .o-mail-DiscussSidebarChannel:contains(Albert)"
+    );
     assert.containsOnce($, ".o-mail-Message:contains(hello world)");
 });
 
@@ -1841,7 +1846,7 @@ QUnit.test("Create a direct message channel when clicking on start a meeting", a
     const { openDiscuss } = await start();
     await openDiscuss(channelId);
     await click("button:contains(Start a meeting)");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(Mitchell Admin)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(Mitchell Admin)");
     assert.containsOnce($, ".o-discuss-Call");
     await waitUntil(".o-discuss-ChannelInvitation");
     assert.containsOnce($, ".o-discuss-ChannelInvitation");
@@ -1857,7 +1862,7 @@ QUnit.test(
         await click(".o-mail-NotificationItem:contains(General)");
         await click("[title='Open Actions Menu']");
         await click("[title='Open in Discuss']");
-        await click(".o-mail-DiscussCategoryItem:contains(General) [title='Channel settings']");
+        await click(".o-mail-DiscussSidebarChannel:contains(General) [title='Channel settings']");
         assert.strictEqual($(".o_breadcrumb").text(), "DiscussGeneral");
     }
 );
diff --git a/addons/mail/static/tests/discuss_app/inbox_tests.js b/addons/mail/static/tests/discuss_app/inbox_tests.js
index 496df9e5206..85be0a85b0a 100644
--- a/addons/mail/static/tests/discuss_app/inbox_tests.js
+++ b/addons/mail/static/tests/discuss_app/inbox_tests.js
@@ -404,13 +404,13 @@ QUnit.test("inbox: mark all messages as read", async (assert) => {
     const { openDiscuss } = await start();
     await openDiscuss();
     assert.containsOnce($, "button:contains(Inbox) .badge:contains(2)");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(General) .badge:contains(2)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(General) .badge:contains(2)");
     assert.containsN($, ".o-mail-Discuss-content .o-mail-Message", 2);
     assert.notOk($("button:contains(Mark all read)")[0].disabled);
 
     await click(".o-mail-Discuss-header button:contains(Mark all read)");
     assert.containsNone($, "button:contains(Inbox) .badge");
-    assert.containsNone($, ".o-mail-DiscussCategoryItem:contains(General) .badge");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel:contains(General) .badge");
     assert.containsNone($, ".o-mail-Message");
     assert.ok($("button:contains(Mark all read)")[0].disabled);
 });
@@ -501,7 +501,7 @@ QUnit.test("inbox messages are never squashed", async (assert) => {
     assert.containsN($, ".o-mail-Message", 2);
     assert.doesNotHaveClass($(".o-mail-Message:contains(body1)"), "o-squashed");
     assert.doesNotHaveClass($(".o-mail-Message:contains(body2)"), "o-squashed");
-    await click(".o-mail-DiscussCategoryItem:contains(test)");
+    await click(".o-mail-DiscussSidebarChannel:contains(test)");
     assert.hasClass($(".o-mail-Message:contains(body2)"), "o-squashed");
 });
 
diff --git a/addons/mail/static/tests/discuss_app/sidebar_tests.js b/addons/mail/static/tests/discuss_app/sidebar_tests.js
index deafa53b54c..6d6897a5927 100644
--- a/addons/mail/static/tests/discuss_app/sidebar_tests.js
+++ b/addons/mail/static/tests/discuss_app/sidebar_tests.js
@@ -25,10 +25,10 @@ QUnit.test("toggling category button hide category items", async (assert) => {
     const { openDiscuss } = await start();
     await openDiscuss();
     assert.containsOnce($, "button.o-active:contains('Inbox')");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel");
 
-    await click(".o-mail-DiscussCategory-icon");
-    assert.containsNone($, ".o-mail-DiscussCategoryItem");
+    await click(".o-mail-DiscussSidebarCategory-icon");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel");
 });
 
 QUnit.test("toggling category button does not hide active category items", async (assert) => {
@@ -39,12 +39,12 @@ QUnit.test("toggling category button does not hide active category items", async
     ]);
     const { openDiscuss } = await start();
     await openDiscuss(channelId);
-    assert.containsN($, ".o-mail-DiscussCategoryItem", 2);
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem.o-active");
+    assert.containsN($, ".o-mail-DiscussSidebarChannel", 2);
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel.o-active");
 
-    await click(".o-mail-DiscussCategory-icon");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem.o-active");
+    await click(".o-mail-DiscussSidebarCategory-icon");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel.o-active");
 });
 
 QUnit.test("Closing a category sends the updated user setting to the server.", async (assert) => {
@@ -60,7 +60,7 @@ QUnit.test("Closing a category sends the updated user setting to the server.", a
         },
     });
     await openDiscuss();
-    await click(".o-mail-DiscussCategory-icon");
+    await click(".o-mail-DiscussSidebarCategory-icon");
     assert.verifySteps(["/web/dataset/call_kw/res.users.settings/set_res_users_settings"]);
 });
 
@@ -82,7 +82,7 @@ QUnit.test("Opening a category sends the updated user setting to the server.", a
         },
     });
     await openDiscuss();
-    await click(".o-mail-DiscussCategory-icon");
+    await click(".o-mail-DiscussSidebarCategory-icon");
     assert.verifySteps(["/web/dataset/call_kw/res.users.settings/set_res_users_settings"]);
 });
 
@@ -105,7 +105,7 @@ QUnit.test(
         });
         const { openDiscuss } = await start();
         await openDiscuss();
-        await click(".o-mail-DiscussCategory-channel span:contains(Channels)");
+        await click(".o-mail-DiscussSidebarCategory-channel span:contains(Channels)");
         assert.containsOnce($, "i[title='View or join channels']");
     }
 );
@@ -142,9 +142,9 @@ QUnit.test("channel - states: close manually by clicking the title", async (asse
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(general)");
-    await click(".o-mail-DiscussCategory-channel span:contains(Channels)");
-    assert.containsNone($, ".o-mail-DiscussCategoryItem:contains(general)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(general)");
+    await click(".o-mail-DiscussSidebarCategory-channel span:contains(Channels)");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel:contains(general)");
 });
 
 QUnit.test("channel - states: open manually by clicking the title", async (assert) => {
@@ -156,9 +156,9 @@ QUnit.test("channel - states: open manually by clicking the title", async (asser
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsNone($, ".o-mail-DiscussCategoryItem:contains(general)");
-    await click(".o-mail-DiscussCategory-channel span:contains(Channels)");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(general)");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel:contains(general)");
+    await click(".o-mail-DiscussSidebarCategory-channel span:contains(Channels)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(general)");
 });
 
 QUnit.test("sidebar: inbox with counter", async (assert) => {
@@ -180,7 +180,7 @@ QUnit.test("default thread rendering", async (assert) => {
     assert.containsOnce($, "button:contains(Inbox)");
     assert.containsOnce($, "button:contains(Starred)");
     assert.containsOnce($, "button:contains(History)");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(General)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(General)");
     assert.hasClass($("button:contains(Inbox)"), "o-active");
     assert.containsOnce(
         $,
@@ -201,8 +201,8 @@ QUnit.test("default thread rendering", async (assert) => {
         ".o-mail-Thread:contains(No history messages  Messages marked as read will appear in the history.)"
     );
 
-    await click(".o-mail-DiscussCategoryItem:contains(General)");
-    assert.hasClass($(".o-mail-DiscussCategoryItem:contains(General)"), "o-active");
+    await click(".o-mail-DiscussSidebarChannel:contains(General)");
+    assert.hasClass($(".o-mail-DiscussSidebarChannel:contains(General)"), "o-active");
     assert.containsOnce($, ".o-mail-Thread:contains(There are no messages in this conversation.)");
 });
 
@@ -213,7 +213,7 @@ QUnit.test("sidebar quick search at 20 or more pinned channels", async (assert)
     }
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsN($, ".o-mail-DiscussCategoryItem", 20);
+    assert.containsN($, ".o-mail-DiscussSidebarChannel", 20);
     assert.containsOnce($, ".o-mail-DiscussSidebar input[placeholder='Quick search...']");
 
     await editInput(
@@ -221,22 +221,22 @@ QUnit.test("sidebar quick search at 20 or more pinned channels", async (assert)
         ".o-mail-DiscussSidebar input[placeholder='Quick search...']",
         "1"
     );
-    assert.containsN($, ".o-mail-DiscussCategoryItem", 11);
+    assert.containsN($, ".o-mail-DiscussSidebarChannel", 11);
 
     await editInput(
         document.body,
         ".o-mail-DiscussSidebar input[placeholder='Quick search...']",
         "12"
     );
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(channel12)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(channel12)");
 
     await editInput(
         document.body,
         ".o-mail-DiscussSidebar input[placeholder='Quick search...']",
         "123"
     );
-    assert.containsNone($, ".o-mail-DiscussCategoryItem");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel");
 });
 
 QUnit.test("sidebar: basic chat rendering", async (assert) => {
@@ -251,14 +251,14 @@ QUnit.test("sidebar: basic chat rendering", async (assert) => {
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(Demo)");
-    const $chat = $(".o-mail-DiscussCategoryItem:contains(Demo)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(Demo)");
+    const $chat = $(".o-mail-DiscussSidebarChannel:contains(Demo)");
     assert.containsOnce($chat, "img[data-alt='Thread Image']");
     assert.containsOnce($chat, "span:contains(Demo)");
-    assert.containsOnce($chat, ".o-mail-DiscussCategoryItem-commands");
+    assert.containsOnce($chat, ".o-mail-DiscussSidebarChannel-commands");
     assert.containsOnce(
         $chat,
-        ".o-mail-DiscussCategoryItem-commands div[title='Unpin Conversation']"
+        ".o-mail-DiscussSidebarChannel-commands div[title='Unpin Conversation']"
     );
     assert.containsNone($chat, ".badge");
 });
@@ -268,7 +268,7 @@ QUnit.test("sidebar: show pinned channel", async (assert) => {
     pyEnv["discuss.channel"].create({ name: "General" });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(General)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(General)");
 });
 
 QUnit.test("sidebar: open pinned channel", async (assert) => {
@@ -276,7 +276,7 @@ QUnit.test("sidebar: open pinned channel", async (assert) => {
     pyEnv["discuss.channel"].create({ name: "General" });
     const { openDiscuss } = await start();
     await openDiscuss();
-    await click(".o-mail-DiscussCategoryItem:contains(General)");
+    await click(".o-mail-DiscussSidebarChannel:contains(General)");
     assert.strictEqual($(".o-mail-Discuss-threadName").val(), "General");
     assert.containsOnce($, ".o-mail-Composer-input[placeholder='Message #General…']");
 });
@@ -302,12 +302,12 @@ QUnit.test("sidebar: open channel and leave it", async (assert) => {
         },
     });
     await openDiscuss();
-    await click(".o-mail-DiscussCategoryItem:contains(General)");
+    await click(".o-mail-DiscussSidebarChannel:contains(General)");
     assert.verifySteps([]);
 
-    await click(".o-mail-DiscussCategoryItem:contains(General) .btn[title='Leave this channel']");
+    await click(".o-mail-DiscussSidebarChannel:contains(General) .btn[title='Leave this channel']");
     assert.verifySteps(["action_unfollow"]);
-    assert.containsNone($, ".o-mail-DiscussCategoryItem:contains(General)");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel:contains(General)");
     assert.notOk($(".o-mail-Discuss-threadName")?.val() === "General");
 });
 
@@ -316,9 +316,9 @@ QUnit.test("sidebar: unpin channel from bus", async (assert) => {
     const channelId = pyEnv["discuss.channel"].create({ name: "General" });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(General)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(General)");
 
-    await click(".o-mail-DiscussCategoryItem:contains(General)");
+    await click(".o-mail-DiscussSidebarChannel:contains(General)");
     assert.strictEqual($(".o-mail-Discuss-threadName").val(), "General");
 
     // Simulate receiving a leave channel notification
@@ -326,7 +326,7 @@ QUnit.test("sidebar: unpin channel from bus", async (assert) => {
     await afterNextRender(() => {
         pyEnv["bus.bus"]._sendone(pyEnv.currentPartner, "discuss.channel/unpin", { id: channelId });
     });
-    assert.containsNone($, ".o-mail-DiscussCategoryItem:contains(General)");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel:contains(General)");
     assert.notOk($(".o-mail-Discuss-threadName")?.val() === "General");
 });
 
@@ -354,7 +354,7 @@ QUnit.test("chat - channel should count unread message [REQUIRE FOCUS]", async (
     assert.containsOnce($, ".o-discuss-badge");
     assert.strictEqual($(".o-discuss-badge").text(), "1");
 
-    await click(".o-mail-DiscussCategoryItem:contains(Demo)");
+    await click(".o-mail-DiscussSidebarChannel:contains(Demo)");
     assert.containsNone($, ".o-discuss-badge");
 });
 
@@ -373,11 +373,11 @@ QUnit.test("mark channel as seen on last message visible [REQUIRE FOCUS]", async
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(test)");
-    assert.hasClass($(".o-mail-DiscussCategoryItem:contains(test)"), "o-unread");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(test)");
+    assert.hasClass($(".o-mail-DiscussSidebarChannel:contains(test)"), "o-unread");
 
-    await click(".o-mail-DiscussCategoryItem:contains(test)");
-    assert.doesNotHaveClass($(".o-mail-DiscussCategoryItem:contains(test)"), "o-unread");
+    await click(".o-mail-DiscussSidebarChannel:contains(test)");
+    assert.doesNotHaveClass($(".o-mail-DiscussSidebarChannel:contains(test)"), "o-unread");
 });
 
 QUnit.test(
@@ -391,7 +391,7 @@ QUnit.test(
         pyEnv["discuss.channel"].create({ name: "general" });
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.containsNone($, ".o-mail-DiscussCategory:contains(Channels) .badge");
+        assert.containsNone($, ".o-mail-DiscussSidebarCategory:contains(Channels) .badge");
     }
 );
 
@@ -433,7 +433,7 @@ QUnit.test(
         ]);
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.containsNone($, ".o-mail-DiscussCategory:contains(Channels) .badge");
+        assert.containsNone($, ".o-mail-DiscussSidebarCategory:contains(Channels) .badge");
     }
 );
 
@@ -448,7 +448,7 @@ QUnit.test(
         });
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.containsNone($, ".o-mail-DiscussCategory:contains(Channels) .badge");
+        assert.containsNone($, ".o-mail-DiscussSidebarCategory:contains(Channels) .badge");
     }
 );
 
@@ -490,7 +490,10 @@ QUnit.test(
         });
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.containsOnce($, ".o-mail-DiscussCategory:contains(Channels) .badge:contains(2)");
+        assert.containsOnce(
+            $,
+            ".o-mail-DiscussSidebarCategory:contains(Channels) .badge:contains(2)"
+        );
     }
 );
 
@@ -510,7 +513,7 @@ QUnit.test(
         });
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.containsNone($, ".o-mail-DiscussCategory:contains(Direct messages) .badge");
+        assert.containsNone($, ".o-mail-DiscussSidebarCategory:contains(Direct messages) .badge");
     }
 );
 
@@ -530,7 +533,7 @@ QUnit.test(
         });
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.containsNone($, ".o-mail-DiscussCategory:contains(Direct messages) .badge");
+        assert.containsNone($, ".o-mail-DiscussSidebarCategory:contains(Direct messages) .badge");
     }
 );
 
@@ -550,7 +553,7 @@ QUnit.test(
         });
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.containsNone($, ".o-mail-DiscussCategory:contains(Direct messages) .badge");
+        assert.containsNone($, ".o-mail-DiscussSidebarCategory:contains(Direct messages) .badge");
     }
 );
 
@@ -586,7 +589,7 @@ QUnit.test(
         await openDiscuss();
         assert.containsOnce(
             $,
-            ".o-mail-DiscussCategory:contains(Direct messages) .badge:contains(2)"
+            ".o-mail-DiscussSidebarCategory:contains(Direct messages) .badge:contains(2)"
         );
     }
 );
@@ -596,7 +599,7 @@ QUnit.test("chat - command: should have add command when category is unfolded",
     await openDiscuss();
     assert.containsOnce(
         $,
-        ".o-mail-DiscussCategory:contains(Direct messages) i[title='Start a conversation']"
+        ".o-mail-DiscussSidebarCategory:contains(Direct messages) i[title='Start a conversation']"
     );
 });
 
@@ -612,7 +615,7 @@ QUnit.test(
         await openDiscuss();
         assert.containsNone(
             $,
-            ".o-mail-DiscussCategory:contains(Direct messages) i[title='Start a conversation']"
+            ".o-mail-DiscussSidebarCategory:contains(Direct messages) i[title='Start a conversation']"
         );
     }
 );
@@ -626,9 +629,9 @@ QUnit.test("chat - states: close manually by clicking the title", async (assert)
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem");
-    await click(".o-mail-DiscussCategory:contains(Direct messages) div");
-    assert.containsNone($, ".o-mail-DiscussCategoryItem");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel");
+    await click(".o-mail-DiscussSidebarCategory:contains(Direct messages) div");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel");
 });
 
 QUnit.test("sidebar channels should be ordered case insensitive alphabetically", async (assert) => {
@@ -643,10 +646,10 @@ QUnit.test("sidebar channels should be ordered case insensitive alphabetically",
     await openDiscuss();
     assert.deepEqual(
         [
-            $(".o-mail-DiscussCategoryItem:eq(0)").text(),
-            $(".o-mail-DiscussCategoryItem:eq(1)").text(),
-            $(".o-mail-DiscussCategoryItem:eq(2)").text(),
-            $(".o-mail-DiscussCategoryItem:eq(3)").text(),
+            $(".o-mail-DiscussSidebarChannel:eq(0)").text(),
+            $(".o-mail-DiscussSidebarChannel:eq(1)").text(),
+            $(".o-mail-DiscussSidebarChannel:eq(2)").text(),
+            $(".o-mail-DiscussSidebarChannel:eq(3)").text(),
         ],
         ["abc", "Abc", "Xyz", "Xyz"]
     );
@@ -673,7 +676,7 @@ QUnit.test("channel - avatar: should have correct avatar", async (assert) => {
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem img");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel img");
     assert.containsOnce(
         $,
         `img[data-src='${getOrigin()}/discuss/channel/${channelId}/avatar_128?unique=100111']`
@@ -721,7 +724,7 @@ QUnit.test("channel - states: close should update the value on the server", asyn
         [[currentUserId]]
     );
     assert.ok(initalSettings.is_discuss_sidebar_category_channel_open);
-    await click(".o-mail-DiscussCategory span:contains(Channels)");
+    await click(".o-mail-DiscussSidebarCategory span:contains(Channels)");
     const newSettings = await env.services.orm.call(
         "res.users.settings",
         "_find_or_create_for_user",
@@ -747,7 +750,7 @@ QUnit.test("channel - states: open should update the value on the server", async
     );
     assert.notOk(initalSettings.is_discuss_sidebar_category_channel_open);
 
-    await click(".o-mail-DiscussCategory span:contains(Channels)");
+    await click(".o-mail-DiscussSidebarCategory span:contains(Channels)");
     const newSettings = await env.services.orm.call(
         "res.users.settings",
         "_find_or_create_for_user",
@@ -773,7 +776,7 @@ QUnit.test("channel - states: close from the bus", async (assert) => {
             },
         });
     });
-    assert.containsOnce($, ".o-mail-DiscussCategory-channel .oi-chevron-right");
+    assert.containsOnce($, ".o-mail-DiscussSidebarCategory-channel .oi-chevron-right");
     assert.containsNone($, "button:contains(channel1)");
 });
 
@@ -794,7 +797,7 @@ QUnit.test("channel - states: open from the bus", async (assert) => {
             },
         });
     });
-    assert.containsOnce($, ".o-mail-DiscussCategory-channel .oi-chevron-down");
+    assert.containsOnce($, ".o-mail-DiscussSidebarCategory-channel .oi-chevron-down");
     assert.containsOnce($, "button:contains(channel1)");
 });
 
@@ -805,11 +808,11 @@ QUnit.test(
         pyEnv["discuss.channel"].create({ name: "channel1" });
         const { openDiscuss } = await start();
         await openDiscuss();
-        await click(".o-mail-DiscussCategoryItem:contains(channel1)");
+        await click(".o-mail-DiscussSidebarChannel:contains(channel1)");
         assert.containsOnce($, "button:contains(channel1).o-active");
 
-        await click(".o-mail-DiscussCategory span:contains(Channels)");
-        assert.containsOnce($, ".o-mail-DiscussCategory-channel .oi-chevron-right");
+        await click(".o-mail-DiscussSidebarCategory span:contains(Channels)");
+        assert.containsOnce($, ".o-mail-DiscussSidebarCategory-channel .oi-chevron-right");
         assert.containsOnce($, "button:contains(channel1)");
 
         await click("button:contains(Inbox)");
@@ -828,7 +831,7 @@ QUnit.test("chat - states: open manually by clicking the title", async (assert)
     });
     const { openDiscuss } = await start();
     await openDiscuss();
-    await click(".o-mail-DiscussCategory-chat span:contains(Direct messages)");
+    await click(".o-mail-DiscussSidebarCategory-chat span:contains(Direct messages)");
     assert.containsOnce($, "button:contains(Mitchell Admin)");
 });
 
@@ -849,7 +852,7 @@ QUnit.test("chat - states: close should call update server data", async (assert)
     );
     assert.ok(initalSettings.is_discuss_sidebar_category_chat_open);
 
-    await click(".o-mail-DiscussCategory-chat span:contains(Direct messages)");
+    await click(".o-mail-DiscussSidebarCategory-chat span:contains(Direct messages)");
     const newSettings = await env.services.orm.call(
         "res.users.settings",
         "_find_or_create_for_user",
@@ -875,7 +878,7 @@ QUnit.test("chat - states: open should call update server data", async (assert)
     );
     assert.notOk(initalSettings.is_discuss_sidebar_category_chat_open);
 
-    await click(".o-mail-DiscussCategory-chat span:contains(Direct messages)");
+    await click(".o-mail-DiscussSidebarCategory-chat span:contains(Direct messages)");
     const newSettings = await env.services.orm.call(
         "res.users.settings",
         "_find_or_create_for_user",
@@ -901,7 +904,7 @@ QUnit.test("chat - states: close from the bus", async (assert) => {
             },
         });
     });
-    assert.containsOnce($, ".o-mail-DiscussCategory-chat .oi-chevron-right");
+    assert.containsOnce($, ".o-mail-DiscussSidebarCategory-chat .oi-chevron-right");
     assert.containsNone($, "button:contains(Mitchell Admin)");
 });
 
@@ -922,7 +925,7 @@ QUnit.test("chat - states: open from the bus", async (assert) => {
             },
         });
     });
-    assert.containsOnce($, ".o-mail-DiscussCategory-chat .oi-chevron-down");
+    assert.containsOnce($, ".o-mail-DiscussSidebarCategory-chat .oi-chevron-down");
     assert.containsOnce($, "button:contains(Mitchell Admin)");
 });
 
@@ -933,18 +936,18 @@ QUnit.test(
         pyEnv["discuss.channel"].create({ channel_type: "chat" });
         const { openDiscuss } = await start();
         await openDiscuss();
-        assert.containsOnce($, ".o-mail-DiscussCategory-chat .oi-chevron-down");
+        assert.containsOnce($, ".o-mail-DiscussSidebarCategory-chat .oi-chevron-down");
         assert.containsOnce($, "button:contains(Mitchell Admin)");
 
         await click("button:contains(Mitchell Admin)");
         assert.containsOnce($, "button:contains(Mitchell Admin).o-active");
 
-        await click(".o-mail-DiscussCategory-chat span:contains(Direct messages)");
-        assert.containsOnce($, ".o-mail-DiscussCategory-chat .oi-chevron-right");
+        await click(".o-mail-DiscussSidebarCategory-chat span:contains(Direct messages)");
+        assert.containsOnce($, ".o-mail-DiscussSidebarCategory-chat .oi-chevron-right");
         assert.containsOnce($, "button:contains(Mitchell Admin)");
 
         await click("button:contains(Inbox)");
-        assert.containsOnce($, ".o-mail-DiscussCategory-chat .oi-chevron-right");
+        assert.containsOnce($, ".o-mail-DiscussSidebarCategory-chat .oi-chevron-right");
         assert.containsNone($, "button:contains(Mitchell Admin)");
     }
 );
@@ -965,7 +968,7 @@ QUnit.test("chat - avatar: should have correct avatar", async (assert) => {
     const { openDiscuss } = await start();
     await openDiscuss();
 
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem img");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel img");
     assert.containsOnce($, `img[data-src='/web/image/res.partner/${partnerId}/avatar_128']`);
 });
 
@@ -1005,7 +1008,7 @@ QUnit.test("chat should be sorted by last activity time [REQUIRE FOCUS]", async
     ]);
     const { openDiscuss } = await start();
     await openDiscuss();
-    let $chats = $(".o-mail-DiscussCategory-chat ~ .o-mail-DiscussCategoryItem");
+    let $chats = $(".o-mail-DiscussSidebarCategory-chat ~ .o-mail-DiscussSidebarChannel");
     assert.strictEqual($chats.length, 2);
     assert.strictEqual($($chats[0]).text(), "Yoshi");
     assert.strictEqual($($chats[1]).text(), "Demo");
@@ -1014,7 +1017,7 @@ QUnit.test("chat should be sorted by last activity time [REQUIRE FOCUS]", async
     await click($($chats[1]));
     await insertText(".o-mail-Composer-input", "Blabla");
     await click(".o-mail-Composer-send");
-    $chats = $(".o-mail-DiscussCategory-chat ~ .o-mail-DiscussCategoryItem");
+    $chats = $(".o-mail-DiscussSidebarCategory-chat ~ .o-mail-DiscussSidebarChannel");
     assert.strictEqual($chats.length, 2);
     assert.strictEqual($($chats[0]).text(), "Demo");
     assert.strictEqual($($chats[1]).text(), "Yoshi");
@@ -1025,9 +1028,9 @@ QUnit.test("Can unpin chat channel", async (assert) => {
     pyEnv["discuss.channel"].create({ channel_type: "chat" });
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(Mitchell Admin)");
-    await click(".o-mail-DiscussCategoryItem [title='Unpin Conversation']");
-    assert.containsNone($, ".o-mail-DiscussCategoryItem:contains(Mitchell Admin)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(Mitchell Admin)");
+    await click(".o-mail-DiscussSidebarChannel [title='Unpin Conversation']");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel:contains(Mitchell Admin)");
 });
 
 QUnit.test("Unpinning chat should display notification", async (assert) => {
@@ -1039,7 +1042,7 @@ QUnit.test("Unpinning chat should display notification", async (assert) => {
         },
     });
     await openDiscuss();
-    await click(".o-mail-DiscussCategoryItem [title='Unpin Conversation']");
+    await click(".o-mail-DiscussSidebarChannel [title='Unpin Conversation']");
     assert.verifySteps(["You unpinned your conversation with Mitchell Admin"]);
 });
 
@@ -1048,7 +1051,7 @@ QUnit.test("Can leave channel", async (assert) => {
     const channelId = pyEnv["discuss.channel"].create({ name: "General" });
     const { env, openDiscuss } = await start();
     await openDiscuss(channelId);
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem:contains(General)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel:contains(General)");
     const messageId = pyEnv["mail.message"].create({
         body: '<div class="o_mail_notification">Mitchell Admin left the channel</div>',
         model: "discuss.channel",
@@ -1062,7 +1065,7 @@ QUnit.test("Can leave channel", async (assert) => {
             [channelId, "discuss.channel/new_message", { id: channelId, message }],
         ]);
     });
-    assert.containsNone($, ".o-mail-DiscussCategoryItem:contains(General)");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel:contains(General)");
 });
 
 QUnit.test("Do no channel_info after unpin", async (assert) => {
@@ -1077,7 +1080,7 @@ QUnit.test("Do no channel_info after unpin", async (assert) => {
         },
     });
     await openDiscuss(channelId);
-    await click(".o-mail-DiscussCategoryItem-commands [title='Unpin Conversation']");
+    await click(".o-mail-DiscussSidebarChannel-commands [title='Unpin Conversation']");
     await afterNextRender(() => {
         env.services.rpc("/mail/message/post", {
             thread_id: channelId,
@@ -1118,8 +1121,8 @@ QUnit.test("Group unread counter up to date after mention is marked as seen", as
     ]);
     const { openDiscuss } = await start();
     await openDiscuss();
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem .o-discuss-badge");
-    await click(".o-mail-DiscussCategoryItem");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel .o-discuss-badge");
+    await click(".o-mail-DiscussSidebarChannel");
     await waitUntil(".o-discuss-badge", 0);
 });
 
@@ -1132,7 +1135,7 @@ QUnit.test("Unpinning channel closes its chat window", async (assert) => {
     await click(".o-mail-NotificationItem");
     assert.containsOnce($, ".o-mail-ChatWindow:contains(Sales)");
     await openDiscuss();
-    await click(".o-mail-DiscussCategoryItem:contains(Sales) [title='Leave this channel']");
+    await click(".o-mail-DiscussSidebarChannel:contains(Sales) [title='Leave this channel']");
     await openFormView("discuss.channel");
     assert.containsNone($, ".o-mail-ChatWindow:contains(Sales)");
 });
diff --git a/addons/mail/static/tests/message/message_tests.js b/addons/mail/static/tests/message/message_tests.js
index 0268aa46c2d..e8709d53d58 100644
--- a/addons/mail/static/tests/message/message_tests.js
+++ b/addons/mail/static/tests/message/message_tests.js
@@ -690,11 +690,11 @@ QUnit.test("redirect to author (open chat)", async (assert) => {
     });
     const { openDiscuss } = await start();
     await openDiscuss(channelId_1);
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem.o-active:contains(General)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel.o-active:contains(General)");
     assert.containsOnce($, ".o-mail-Discuss-content .o-mail-Message-avatarContainer img");
 
     await click(".o-mail-Discuss-content .o-mail-Message-avatarContainer img");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem.o-active:contains(Demo)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel.o-active:contains(Demo)");
 });
 
 QUnit.test("open chat from avatar should not work on self-authored messages", async (assert) => {
@@ -720,7 +720,7 @@ QUnit.test("open chat from avatar should not work on self-authored messages", as
     // try to click on self, to test it doesn't work
     click(".o-mail-Message-avatar").catch(() => {});
     await nextAnimationFrame();
-    assert.containsNone($, ".o-mail-DiscussCategoryItem.o-active:contains(Mitchell Admin)");
+    assert.containsNone($, ".o-mail-DiscussSidebarChannel.o-active:contains(Mitchell Admin)");
     assert.containsNone($, ".breadcrumb:contains(Mitchell Admin)"); // should not open form view neither
 });
 
@@ -1500,7 +1500,7 @@ QUnit.test("Mark as unread", async (assert) => {
     await click("[title='Expand']");
     await click("[title='Mark as Unread']");
     assert.containsOnce($, ".o-mail-Thread-newMessage");
-    assert.containsOnce($, ".o-mail-DiscussCategoryItem .badge:contains(1)");
+    assert.containsOnce($, ".o-mail-DiscussSidebarChannel .badge:contains(1)");
 });
 
 QUnit.test("Avatar of unknown author", async (assert) => {
diff --git a/addons/mail/static/tests/thread/thread_tests.js b/addons/mail/static/tests/thread/thread_tests.js
index 1c52f316198..a4d94be1ea8 100644
--- a/addons/mail/static/tests/thread/thread_tests.js
+++ b/addons/mail/static/tests/thread/thread_tests.js
@@ -175,12 +175,12 @@ QUnit.test(
         await openDiscuss(channelId_1);
         const scrolltop_1 = $(".o-mail-Thread")[0].scrollHeight / 2;
         $(".o-mail-Thread")[0].scrollTo({ top: scrolltop_1 });
-        await click(".o-mail-DiscussCategoryItem:contains(channel-2)");
+        await click(".o-mail-DiscussSidebarChannel:contains(channel-2)");
         const scrolltop_2 = $(".o-mail-Thread")[0].scrollHeight / 3;
         $(".o-mail-Thread")[0].scrollTo({ top: scrolltop_2 });
-        await click(".o-mail-DiscussCategoryItem:contains(channel-1)");
+        await click(".o-mail-DiscussSidebarChannel:contains(channel-1)");
         assert.ok(isScrolledTo($(".o-mail-Thread")[0], scrolltop_1));
-        await click(".o-mail-DiscussCategoryItem:contains(channel-2)");
+        await click(".o-mail-DiscussSidebarChannel:contains(channel-2)");
         assert.ok(isScrolledTo($(".o-mail-Thread")[0], scrolltop_2));
     }
 );
@@ -869,11 +869,11 @@ QUnit.test("Thread messages are only loaded once", async (assert) => {
         },
     ]);
     await openDiscuss();
-    await click(".o-mail-DiscussCategoryItem:eq(0)");
+    await click(".o-mail-DiscussSidebarChannel:eq(0)");
     await waitUntil(".o-mail-Message:contains(channel1)");
-    await click(".o-mail-DiscussCategoryItem:eq(1)");
+    await click(".o-mail-DiscussSidebarChannel:eq(1)");
     await waitUntil(".o-mail-Message:contains(channel2)");
-    await click(".o-mail-DiscussCategoryItem:eq(0)");
+    await click(".o-mail-DiscussSidebarChannel:eq(0)");
     await waitUntil(".o-mail-Message:contains(channel1)");
     assert.verifySteps([`load messages - ${channelIds[0]}`, `load messages - ${channelIds[1]}`]);
 });
@@ -983,7 +983,7 @@ QUnit.test("can be marked as read while loading", async function (assert) {
     });
     await openDiscuss(undefined, { waitUntilMessagesLoaded: false });
     assert.containsOnce($, ".o-discuss-badge:contains(1)");
-    await click(".o-mail-DiscussCategoryItem:contains(Demo)");
+    await click(".o-mail-DiscussSidebarChannel:contains(Demo)");
     await afterNextRender(loadDeferred.resolve);
     assert.containsNone($, ".o-discuss-badge");
 });