diff --git a/addons/mail/i18n/mail.pot b/addons/mail/i18n/mail.pot
index b040c6472c1..8173fdfb904 100644
--- a/addons/mail/i18n/mail.pot
+++ b/addons/mail/i18n/mail.pot
@@ -2881,13 +2881,6 @@ msgstr ""
 msgid "Document: \""
 msgstr ""
 
-#. module: mail
-#. odoo-javascript
-#: code:addons/mail/static/src/core/common/message.js:0
-#, python-format
-msgid "Don't show Original Email"
-msgstr ""
-
 #. module: mail
 #. odoo-javascript
 #: code:addons/mail/static/src/core/web/activity_list_popover.xml:0
@@ -8238,13 +8231,6 @@ msgstr ""
 msgid "Show Member List"
 msgstr ""
 
-#. module: mail
-#. odoo-javascript
-#: code:addons/mail/static/src/core/common/message.js:0
-#, python-format
-msgid "Show Original Email"
-msgstr ""
-
 #. module: mail
 #. odoo-javascript
 #: code:addons/mail/static/src/discuss/core/common/channel_commands.js:0
diff --git a/addons/mail/static/src/core/common/message.js b/addons/mail/static/src/core/common/message.js
index ca1a0187464..ad774c7808f 100644
--- a/addons/mail/static/src/core/common/message.js
+++ b/addons/mail/static/src/core/common/message.js
@@ -90,11 +90,6 @@ export class Message extends Component {
     ];
     static template = "mail.Message";
 
-    /** @type {HTMLStyleElement} */
-    shadowStyle;
-    /** @type {ShadowRoot} */
-    shadowRoot;
-
     setup() {
         this.popover = usePopover(this.constructor.components.Popover, { position: "top" });
         this.state = useState({
@@ -102,7 +97,6 @@ export class Message extends Component {
             isHovered: false,
             isClicked: false,
             expandOptions: false,
-            originalFormat: false,
             emailHeaderOpen: false,
             showTranslation: false,
         });
@@ -132,19 +126,6 @@ export class Message extends Component {
             },
             () => [this.props.messageEdition?.editingMessage]
         );
-        useEffect(
-            () => {
-                if (!this.shadowRoot) {
-                    return;
-                }
-                if (this.state.originalFormat) {
-                    this.shadowRoot.removeChild(this.shadowStyle);
-                } else {
-                    this.shadowRoot.insertBefore(this.shadowStyle, this.shadowRoot.firstChild);
-                }
-            },
-            () => [this.state.originalFormat]
-        );
         onPatched(() => {
             if (this.props.highlighted && this.root.el) {
                 this.root.el.scrollIntoView({ behavior: "smooth", block: "center" });
@@ -155,14 +136,14 @@ export class Message extends Component {
                 this.prepareMessageBody(this.messageBody.el);
             }
             if (this.shadowBody.el) {
-                this.shadowRoot = this.shadowBody.el.attachShadow({ mode: "open" });
+                const shadowRoot = this.shadowBody.el.attachShadow({ mode: "open" });
                 const body = document.createElement("span");
                 body.innerHTML =
                     this.props.messageSearch?.highlight(this.message.body) ?? this.message.body;
                 this.prepareMessageBody(body);
                 const color = cookie.get("color_scheme") === "dark" ? "white" : "black";
-                this.shadowStyle = document.createElement("style");
-                this.shadowStyle.innerHTML = `
+                const shadowStyle = document.createElement("style");
+                shadowStyle.innerHTML = `
                     * {
                         background-color: transparent !important;
                         color: ${color} !important;
@@ -177,8 +158,10 @@ export class Message extends Component {
                         background: ${this.constructor.SHADOW_HIGHLIGHT_COLOR} !important;
                     }
                 `;
-                this.shadowRoot.appendChild(this.shadowStyle);
-                this.shadowRoot.appendChild(body);
+                if (cookie.get("color_scheme") === "dark") {
+                    shadowRoot.appendChild(shadowStyle);
+                }
+                shadowRoot.appendChild(body);
             }
         });
     }
@@ -213,7 +196,8 @@ export class Message extends Component {
 
     get authorAvatarUrl() {
         if (
-            this.message.type === "email" &&
+            this.message.type &&
+            this.message.type.includes("email") &&
             !["partner", "guest"].includes(this.message.author?.type)
         ) {
             return url("/mail/static/src/img/email_icon.png");
diff --git a/addons/mail/static/src/core/common/message.scss b/addons/mail/static/src/core/common/message.scss
index 8f8242901df..e7724af3740 100644
--- a/addons/mail/static/src/core/common/message.scss
+++ b/addons/mail/static/src/core/common/message.scss
@@ -59,14 +59,6 @@
     z-index: $o-mail-NavigableList-zIndex;
 }
 
-.o-mail-Message-originalFormat {
-    line-height: 1;
-
-    &:hover {
-        background-color: rgba(0, 0, 0, 0.075);
-    }
-}
-
 .o-mail-Message-searchHighlight {
     background: rgba($warning, 0.75);
 }
diff --git a/addons/mail/static/src/core/common/message.xml b/addons/mail/static/src/core/common/message.xml
index 8b8f72d401a..ba9818f35b1 100644
--- a/addons/mail/static/src/core/common/message.xml
+++ b/addons/mail/static/src/core/common/message.xml
@@ -90,12 +90,8 @@
                                                             }" t-ref="body">
                                                     <Composer t-if="state.isEditing" autofocus="true" composer="message.composer" messageComponent="constructor" onDiscardCallback.bind="exitEditMode" onPostCallback.bind="exitEditMode" mode="env.inChatter ? 'extended' : 'compact'" sidebar="false"/>
                                                     <t t-else="">
-                                                        <button t-if="message.type === 'email'" class="o-mail-Message-originalFormat float-end p-1 mb-1 btn btn-link opacity-75 fst-italic" t-att-class="env.inChatWindow and isAlignedRight ? 'me-3' : 'ms-3'" t-on-click="() => this.state.originalFormat = !this.state.originalFormat">
-                                                            <t t-if="state.originalFormat">Show Custom Format</t>
-                                                            <t t-else="">Show Original Format</t>
-                                                        </button>
                                                         <em t-if="message.subject and !message.isSubjectSimilarToOriginThreadName and !message.isSubjectDefault" class="mb-1 me-2">Subject: <t t-out="props.messageSearch?.highlight(message.subject) ?? message.subject"/></em>
-                                                        <div t-if="message.type === 'email'" t-ref="shadowBody"/>
+                                                        <div t-if="message.type and message.type.includes('email')" t-ref="shadowBody"/>
                                                         <t t-elif="state.showTranslation" t-out="message.translationValue"/>
                                                         <t t-elif="message.body" t-out="props.messageSearch?.highlight(message.body) ?? message.body"/>
                                                         <p class="fst-italic text-muted small" t-if="state.showTranslation">
diff --git a/addons/mail/static/src/core/common/message_in_reply.js b/addons/mail/static/src/core/common/message_in_reply.js
index 08372ebcc7a..63e4a23fe5a 100644
--- a/addons/mail/static/src/core/common/message_in_reply.js
+++ b/addons/mail/static/src/core/common/message_in_reply.js
@@ -17,7 +17,8 @@ export class MessageInReply extends Component {
 
     get authorAvatarUrl() {
         if (
-            this.message.type === "email" &&
+            this.message.type &&
+            this.message.type.includes("email") &&
             !["partner", "guest"].includes(this.props.message.author?.type)
         ) {
             return url("/mail/static/src/img/email_icon.png");