diff --git a/addons/mail/static/src/js/discuss.js b/addons/mail/static/src/js/discuss.js
index 79a13c307c8..7b56282565a 100644
--- a/addons/mail/static/src/js/discuss.js
+++ b/addons/mail/static/src/js/discuss.js
@@ -344,7 +344,9 @@ var Discuss = AbstractAction.extend({
     on_detach_callback: function () {
         this._super();
         this.call('mail_service', 'getMailBus').trigger('discuss_open', false);
-        this._threadsScrolltop[this._thread.getID()] = this._threadWidget.getScrolltop();
+        if (this._thread) {
+            this._threadsScrolltop[this._thread.getID()] = this._threadWidget.getScrolltop();
+        }
     },
 
     //--------------------------------------------------------------------------
diff --git a/addons/mail/static/tests/discuss_tests.js b/addons/mail/static/tests/discuss_tests.js
index 8cf73248754..7ef73123e4d 100644
--- a/addons/mail/static/tests/discuss_tests.js
+++ b/addons/mail/static/tests/discuss_tests.js
@@ -307,10 +307,6 @@ QUnit.test('searchview filter messages', async function (assert) {
                 '</search>',
         },
     });
-    // needed to handle events triggered by the controlPanelModel
-    discuss.on_attach_callback();
-    await testUtils.nextTick();
-
     assert.containsN(discuss, '.o_thread_message', 2,
         "there should be two messages in the inbox mailbox");
     assert.strictEqual($('.o_searchview_input').length, 1,
@@ -343,7 +339,6 @@ QUnit.test('searchview filter messages', async function (assert) {
         "No matches found",
         "should display that there are no matching messages");
 
-    discuss.on_detach_callback();
     discuss.destroy();
 
 });
@@ -1981,10 +1976,6 @@ QUnit.test('save filter discuss', async function (assert) {
             }
         }
     });
-    // needed to handle events triggered by the controlPanelModel
-    discuss.on_attach_callback();
-    await testUtils.nextTick();
-
     assert.containsOnce(discuss, '.o_searchview_input_container', 'search view input present');
 
     await cpHelpers.editSearch(discuss, "she was born in a hurricane");
@@ -1999,7 +1990,6 @@ QUnit.test('save filter discuss', async function (assert) {
     await cpHelpers.editFavoriteName(discuss, "War");
     await cpHelpers.saveFavorite(discuss);
 
-    discuss.on_detach_callback();
     discuss.destroy();
 });
 
diff --git a/addons/mail/static/tests/helpers/test_utils.js b/addons/mail/static/tests/helpers/test_utils.js
index f3328c9a1a9..529f2aa6d70 100644
--- a/addons/mail/static/tests/helpers/test_utils.js
+++ b/addons/mail/static/tests/helpers/test_utils.js
@@ -9,12 +9,13 @@ var mailUtils = require('mail.utils');
 
 var AbstractStorageService = require('web.AbstractStorageService');
 var Class = require('web.Class');
+const dom = require('web.dom');
 var RamStorage = require('web.RamStorage');
 const makeTestEnvironment = require('web.test_env');
 var testUtils = require('web.test_utils');
 var Widget = require('web.Widget');
 
-const { prepareTarget, nextTick } = testUtils;
+const { prepareTarget } = testUtils;
 /**
  * Test Utils
  *
@@ -30,31 +31,38 @@ const { prepareTarget, nextTick } = testUtils;
  * @returns {Promise<Discuss>}
  */
 async function createDiscuss(params) {
-    var Parent = Widget.extend({
+    const target = prepareTarget(params.debug);
+    const Parent = Widget.extend({
         do_push_state: function () {},
     });
-    var parent = new Parent();
+    const parent = new Parent();
     params.archs = params.archs || {
         'mail.message,false,search': '<search/>',
     };
-    testUtils.mock.addMockEnvironment(parent, params);
+    await testUtils.mock.addMockEnvironment(parent, params);
 
     const env = params.env || {};
     owl.Component.env = makeTestEnvironment(env);
 
-    var discuss = new Discuss(parent, params);
+    const discuss = new Discuss(parent, params);
 
     // override 'destroy' of discuss so that it calls 'destroy' on the parent
     // instead, which is the parent of discuss and the mockServer.
+    const _destroy = discuss.destroy;
     discuss.destroy = function () {
         // remove the override to properly destroy discuss and its children
         // when it will be called the second time (by its parent)
-        delete discuss.destroy;
+        discuss.destroy = _destroy;
+        discuss.on_detach_callback();
         parent.destroy();
     };
 
-    await discuss.appendTo(prepareTarget(params.debug));
-    await nextTick();
+    const fragment = document.createDocumentFragment();
+    await discuss.appendTo(fragment);
+    dom.prepend(target, fragment, {
+        callbacks: [{ widget: discuss }],
+        in_DOM: true,
+    });
     return discuss;
 }