diff --git a/app/globals.css b/app/globals.css
index fb908a2db..4dd7d9d64 100644
--- a/app/globals.css
+++ b/app/globals.css
@@ -780,6 +780,11 @@ optgroup {
   outline: none;
 }
 
+/* View-only quote decorations must survive a node view refreshing its inline styles. */
+.tiptap [data-reply-quote-collapsed] {
+  display: none !important;
+}
+
 .tiptap p {
   margin: 0.25rem 0;
 }
diff --git a/components/email/__tests__/composer-reply-signature.test.tsx b/components/email/__tests__/composer-reply-signature.test.tsx
index 2cb02c410..9205d4c35 100644
--- a/components/email/__tests__/composer-reply-signature.test.tsx
+++ b/components/email/__tests__/composer-reply-signature.test.tsx
@@ -316,3 +316,37 @@ describe('reply signature above the quote (#842)', () => {
     expect(sent.body).toMatch(/Original text[\s\S]*Sales team$/);
   });
 });
+
+
+describe('reply quote attribution markers', () => {
+  afterEach(() => {
+    useSettingsStore.setState({ plainTextMode: false, signaturePosition: 'below_quote' });
+  });
+
+  it.each(['reply', 'replyAll'] as const)('marks the HTML original in %s mode', (mode) => {
+    render(<EmailComposer mode={mode} replyTo={TO_ME} />);
+    const html = screen.getByTestId('rich-text-editor').getAttribute('data-html')!;
+    expect(html).toContain('data-reply-quote-start="true"');
+    expect(html).toContain('Original text');
+  });
+
+  it('marks the attribution of a plain-text original composed in rich-text mode', () => {
+    render(<EmailComposer mode="reply" replyTo={{ ...TO_ME, htmlBody: undefined }} />);
+    const html = screen.getByTestId('rich-text-editor').getAttribute('data-html')!;
+    expect(html).toContain('data-reply-quote-start="true"');
+    expect(html).toContain('<blockquote');
+  });
+
+  it('leaves forwarding attribution unmarked', () => {
+    render(<EmailComposer mode="forward" replyTo={TO_ME} />);
+    const html = screen.getByTestId('rich-text-editor').getAttribute('data-html')!;
+    expect(html).not.toContain('data-reply-quote-start');
+    expect(html).toContain('Original text');
+  });
+
+  it('preserves a simple plugin attribution', () => {
+    render(<EmailComposer mode="reply" replyTo={{ ...TO_ME, quoteHeaderHtml: '<p><b>From:</b> Bob</p>', quoteWrapInBlockquote: false }} />);
+    const html = screen.getByTestId('rich-text-editor').getAttribute('data-html')!;
+    expect(html).toContain('<p data-reply-quote-start="true"><b>From:</b> Bob</p>');
+  });
+});
diff --git a/components/email/__tests__/reply-quote-collapse.test.ts b/components/email/__tests__/reply-quote-collapse.test.ts
new file mode 100644
index 000000000..86c22986c
--- /dev/null
+++ b/components/email/__tests__/reply-quote-collapse.test.ts
@@ -0,0 +1,170 @@
+import { afterEach, describe, expect, it } from 'vitest';
+import { Editor } from '@tiptap/core';
+import StarterKit from '@tiptap/starter-kit';
+import Paragraph from '@tiptap/extension-paragraph';
+import { trailingParagraphBreakRule } from '../paragraph-breaks';
+import { QuotedHtml, buildQuotedHtmlBlock, serializeEditorContent } from '../quoted-html';
+import { SignatureBlock, buildSignatureBlock } from '../signature-block';
+import { ReplyQuoteCollapse, markReplyQuoteHeader } from '../reply-quote-collapse';
+
+const HEADER = markReplyQuoteHeader('<div>On Monday, Bob wrote:<br></div>');
+const ORIGINAL = '<p>Original message</p><img src="cid:logo"><blockquote>Earlier reply</blockquote>';
+const QUOTE = buildQuotedHtmlBlock(ORIGINAL);
+const ReplyParagraph = Paragraph.extend({
+  parseHTML() {
+    return [...(this.parent?.() ?? []), trailingParagraphBreakRule];
+  },
+});
+let editor: Editor | undefined;
+
+function mount(html = `<p>My response</p>${HEADER}${QUOTE}`) {
+  editor = new Editor({
+    extensions: [StarterKit.configure({ paragraph: false }), ReplyParagraph, QuotedHtml, SignatureBlock, ReplyQuoteCollapse],
+    content: html,
+  });
+  // Settle StarterKit's trailing paragraph before comparing message data.
+  editor.view.dispatch(editor.state.tr);
+  document.body.appendChild(editor.view.dom);
+  return editor;
+}
+function toggle() {
+  return editor!.view.dom.querySelector<HTMLButtonElement>('[data-reply-quote-toggle]')!;
+}
+function quote() {
+  return editor!.view.dom.querySelector<HTMLElement>('.quoted-html-island, blockquote')!;
+}
+afterEach(() => {
+  editor?.destroy();
+  editor = undefined;
+  document.body.innerHTML = '';
+});
+
+describe('reply quote visibility', () => {
+  it('starts collapsed, hides attribution too, and toggles without changing serialized content', () => {
+    const e = mount();
+    const saved = serializeEditorContent(e);
+    expect(toggle()).toHaveAttribute('aria-expanded', 'false');
+    expect(toggle()).toHaveAccessibleName('Show quoted text');
+    expect(quote()).toHaveAttribute('data-reply-quote-collapsed', 'true');
+    expect(e.view.dom.querySelector('[data-reply-quote-start]')).toHaveAttribute('data-reply-quote-collapsed', 'true');
+    expect(saved).toContain('On Monday, Bob wrote:');
+    expect(saved).toContain(ORIGINAL);
+    expect(saved).not.toContain('data-reply-quote-toggle');
+    expect(saved).not.toContain('display: none');
+    expect(saved).not.toContain('data-reply-quote-collapsed');
+    toggle().click();
+    expect(toggle()).toHaveAttribute('aria-expanded', 'true');
+    expect(quote()).not.toHaveAttribute('data-reply-quote-collapsed');
+    expect(serializeEditorContent(e)).toBe(saved);
+    toggle().click();
+    expect(toggle()).toHaveAttribute('aria-expanded', 'false');
+    expect(serializeEditorContent(e)).toBe(saved);
+  });
+
+  it('round-trips a collapsed quote through a native draft without dropping inline images', () => {
+    const e = mount();
+    const saved = serializeEditorContent(e);
+    e.commands.setContent(saved);
+    expect(toggle()).toHaveAttribute('aria-expanded', 'false');
+    expect(serializeEditorContent(e)).toBe(saved);
+    expect(saved).toContain('src="cid:logo"');
+  });
+
+  it('collapses a plain-text original in rich-text mode and leaves an authored blockquote visible', () => {
+    mount(`<p>Response</p><blockquote>My own quotation</blockquote>${HEADER}<blockquote>Original plain-text message</blockquote>`);
+    const quotes = editor!.view.dom.querySelectorAll<HTMLElement>('blockquote');
+    expect(quotes[0]).not.toHaveAttribute('data-reply-quote-collapsed');
+    expect(quotes[1]).toHaveAttribute('data-reply-quote-collapsed', 'true');
+  });
+
+  it.each(['above', 'below'])('keeps the signature visible %s the quoted original', (position) => {
+    const signature = buildSignatureBlock('<b>My signature</b>');
+    const e = mount(`<p>Response</p>${position === 'above' ? signature : ''}${HEADER}${QUOTE}${position === 'below' ? signature : ''}`);
+    const signatureNode = e.view.dom.querySelector<HTMLElement>('[data-signature-html]');
+    expect(serializeEditorContent(e)).toContain('My signature');
+    // Every hidden top-level block belongs to the attribution/original pair.
+    const hidden = e.view.dom.querySelectorAll('[data-reply-quote-collapsed]');
+    expect(hidden).toHaveLength(2);
+    expect(signatureNode?.style.display ?? '').toBe('');
+  });
+
+  it('keeps edited quote content when collapsed and serialized', async () => {
+    const e = mount();
+    toggle().click();
+    const inner = quote().shadowRoot!.firstElementChild as HTMLElement;
+    inner.querySelector('p')!.textContent = 'Edited original';
+    inner.dispatchEvent(new Event('input', { bubbles: true, composed: true }));
+    await new Promise((resolve) => requestAnimationFrame(resolve));
+    toggle().click();
+    expect(serializeEditorContent(e)).toContain('Edited original');
+    expect(serializeEditorContent(e)).toContain('src="cid:logo"');
+  });
+
+  it('keeps the quote hidden when its node view updates while collapsed', () => {
+    const e = mount();
+    let quotePos = 0;
+    e.state.doc.forEach((node, pos) => { if (node.type.name === 'quotedHtml') quotePos = pos; });
+    const node = e.state.doc.nodeAt(quotePos)!;
+    e.view.dispatch(e.state.tr.setNodeMarkup(quotePos, undefined, { ...node.attrs, html: '<p>Updated original</p>' }));
+    expect(toggle()).toHaveAttribute('aria-expanded', 'false');
+    expect(quote()).toHaveAttribute('data-reply-quote-collapsed', 'true');
+    expect(serializeEditorContent(e)).toContain('Updated original');
+  });
+
+  it('does not add visibility toggles to Undo history', () => {
+    const e = mount();
+    e.commands.insertContentAt(1, 'Added ');
+    toggle().click();
+    toggle().click();
+    e.commands.undo();
+    expect(serializeEditorContent(e)).not.toContain('Added ');
+    expect(serializeEditorContent(e)).toContain(ORIGINAL);
+    e.commands.redo();
+    expect(serializeEditorContent(e)).toContain('Added ');
+  });
+
+  it('reveals a quote reached with a text selection and moves the caret out when collapsed', () => {
+    const e = mount();
+    const start = Number(toggle().dataset.replyQuoteToggle);
+    e.commands.setTextSelection(start + 1);
+    expect(toggle()).toHaveAttribute('aria-expanded', 'true');
+    toggle().click();
+    expect(toggle()).toHaveAttribute('aria-expanded', 'false');
+    expect(e.state.selection.to).toBeLessThanOrEqual(start);
+  });
+
+  it('retains keyboard focus on the toggle when expanding or collapsing', () => {
+    mount();
+    toggle().focus();
+    toggle().click();
+    expect(toggle()).toHaveFocus();
+    toggle().click();
+    expect(toggle()).toHaveFocus();
+  });
+
+  it('preserves expansion when the authored response changes before the quote', () => {
+    const e = mount();
+    toggle().click();
+    e.commands.insertContentAt(1, 'More text. ');
+    expect(toggle()).toHaveAttribute('aria-expanded', 'true');
+    expect(quote()).not.toHaveAttribute('data-reply-quote-collapsed');
+  });
+
+  it.each([
+    `<p>Forwarded message</p>${QUOTE}`,
+    '<p>Old draft</p><blockquote>Unknown attribution</blockquote>',
+    `${HEADER}<p>New authored paragraph</p><blockquote>Authored quote</blockquote>`,
+    `${HEADER}<blockquote></blockquote>`,
+  ])('leaves unmarked, ambiguous or empty quote content visible', (html) => {
+    mount(html);
+    expect(toggle()).toBeNull();
+    expect(editor!.view.dom.querySelector('[data-reply-quote-collapsed]')).toBeNull();
+  });
+
+  it('preserves an unrecognized plugin header and recognizes a simple plugin paragraph', () => {
+    const unknown = '<section><div><p>Custom header</p></div></section>';
+    expect(markReplyQuoteHeader(unknown)).toBe(unknown);
+    mount(`<p>Response</p>${markReplyQuoteHeader('<p><b>From:</b> Bob</p>')}${QUOTE}`);
+    expect(toggle()).toHaveAttribute('aria-expanded', 'false');
+  });
+});
diff --git a/components/email/email-composer.tsx b/components/email/email-composer.tsx
index 75f1129d3..51f6d0347 100644
--- a/components/email/email-composer.tsx
+++ b/components/email/email-composer.tsx
@@ -56,6 +56,7 @@ import { sanitizeSignatureHtml, sanitizeSignatureHtmlForDisplay, sanitizeEmailHt
 import { buildReplySubject, buildForwardSubject } from "@/lib/subject-prefix";
 import { isFilePreviewable } from "@/lib/file-preview";
 import { isEditableEventTarget } from "@/lib/keyboard";
+import { markReplyQuoteHeader } from "@/components/email/reply-quote-collapse";
 import { buildQuotedHtmlBlock, serializeEditorContent } from "@/components/email/quoted-html";
 import { containsEmbeddedSignature } from "@/components/email/signature-block";
 import {
@@ -729,6 +730,10 @@ export function EmailComposer({
     const { externalContentPolicy, isSenderTrusted } = useSettingsStore.getState();
     const quoteRemoteAllowed = externalContentPolicy === 'allow' || (!!from?.email && isSenderTrusted(from.email));
 
+    const replyHeader = (html: string) => mode === 'reply' || mode === 'replyAll'
+      ? markReplyQuoteHeader(html)
+      : html;
+
     // Plugin override (resolved at composer open via onBuildQuoteHeader).
     if (replyTo.quoteHeaderHtml !== undefined && (mode === 'reply' || mode === 'replyAll' || mode === 'forward')) {
       if (replyTo.htmlBody) {
@@ -739,7 +744,7 @@ export function EmailComposer({
           rewriteCidImagesForEditor(sanitizeEmailHtml(replyTo.htmlBody)),
           { remoteAllowed: quoteRemoteAllowed, showQuoteBorder: replyTo.quoteWrapInBlockquote !== false },
         );
-        return `${prefix}${signatureBlock}<br>${replyTo.quoteHeaderHtml}${island}`;
+        return `${prefix}${signatureBlock}<br>${replyHeader(replyTo.quoteHeaderHtml)}${island}`;
       }
       const escaped = replyTo.body
         ? replyTo.body.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/\n/g, '<br>')
@@ -748,7 +753,7 @@ export function EmailComposer({
       const bodyHtml = wrap
         ? `<blockquote style="margin:0 0 0 0.8ex;border-left:2px solid #ccc;padding-left:1ex">${escaped}</blockquote>`
         : escaped;
-      return `${prefix}${signatureBlock}<br>${replyTo.quoteHeaderHtml}${bodyHtml}`;
+      return `${prefix}${signatureBlock}<br>${replyHeader(replyTo.quoteHeaderHtml)}${bodyHtml}`;
     }
 
     // Build quoted content as HTML
@@ -766,7 +771,7 @@ export function EmailComposer({
         rewriteCidImagesForEditor(sanitizeEmailHtml(replyTo.htmlBody)),
         { remoteAllowed: quoteRemoteAllowed },
       );
-      return `${prefix}${signatureBlock}<br><div>${quoteHeader}</div>${island}`;
+      return `${prefix}${signatureBlock}<br>${replyHeader(`<div>${quoteHeader}</div>`)}${island}`;
     }
 
     if (replyTo.body) {
@@ -774,7 +779,7 @@ export function EmailComposer({
       if (mode === 'forward') {
         return `${prefix}${signatureBlock}<br><br>${tQuote('forwarded_separator')}<br>${tQuote('from_label')}: ${escapeHtml(fromStrFull)}<br>${tQuote('date_label')}: ${escapeHtml(date)}<br>${tQuote('subject_label')}: ${escapeHtml(replyTo.subject || '')}<br><br>${escapedOriginal}`;
       } else if (mode === 'reply' || mode === 'replyAll') {
-        return `${prefix}${signatureBlock}<br><br>${tQuote('reply_line', { date: escapeHtml(date), from: escapeHtml(fromStrFull) })}<br><blockquote style="margin:0 0 0 0.8ex;border-left:2px solid #ccc;padding-left:1ex">${escapedOriginal}</blockquote>`;
+        return `${prefix}${signatureBlock}<br><br>${replyHeader(`<p>${tQuote('reply_line', { date: escapeHtml(date), from: escapeHtml(fromStrFull) })}<br></p>`)}<blockquote style="margin:0 0 0 0.8ex;border-left:2px solid #ccc;padding-left:1ex">${escapedOriginal}</blockquote>`;
       }
     }
     return prefix;
diff --git a/components/email/reply-quote-collapse.ts b/components/email/reply-quote-collapse.ts
new file mode 100644
index 000000000..1fcb218b6
--- /dev/null
+++ b/components/email/reply-quote-collapse.ts
@@ -0,0 +1,151 @@
+"use client";
+
+import { Extension } from '@tiptap/core';
+import type { Node as PMNode } from '@tiptap/pm/model';
+import { Plugin, PluginKey, Selection } from '@tiptap/pm/state';
+import { Decoration, DecorationSet } from '@tiptap/pm/view';
+
+const START_ATTRIBUTE = 'data-reply-quote-start';
+const HEADER_BLOCKS = 'p, h1, h2, h3, h4, h5, h6, table, ul, ol, pre, blockquote';
+
+/** Mark only attribution generated for a reply. Unknown plugin markup stays visible. */
+export function markReplyQuoteHeader(html: string): string {
+  if (typeof document === 'undefined') return html;
+  // A template is inert: attribution containing an image must not load it here.
+  const template = document.createElement('template');
+  template.innerHTML = html;
+  const first = template.content.firstElementChild;
+  if (!first) return `<p ${START_ATTRIBUTE}="true">${html}</p>`;
+  // The default attribution is a div of inline content, parsed as a paragraph
+  // by the editor. Make that paragraph explicit so its marker round-trips.
+  if (first.tagName === 'DIV' && !first.querySelector(HEADER_BLOCKS)) {
+    const paragraph = document.createElement('p');
+    for (const attribute of first.attributes) paragraph.setAttribute(attribute.name, attribute.value);
+    paragraph.innerHTML = first.innerHTML;
+    first.replaceWith(paragraph);
+    paragraph.setAttribute(START_ATTRIBUTE, 'true');
+  } else if (first.matches(HEADER_BLOCKS)) {
+    first.setAttribute(START_ATTRIBUTE, 'true');
+  } else {
+    return html;
+  }
+  // A leading text node would otherwise remain visible outside the group.
+  if (template.content.firstChild?.nodeType === Node.TEXT_NODE
+    && template.content.firstChild.textContent?.trim()) return html;
+  return template.innerHTML;
+}
+
+interface QuoteRange { from: number; to: number }
+interface QuoteState { expanded: Set<number> }
+const quoteKey = new PluginKey<QuoteState>('replyQuoteCollapse');
+
+function quoteRanges(doc: PMNode): QuoteRange[] {
+  const ranges: QuoteRange[] = [];
+  let start: number | null = null;
+  doc.forEach((node, pos) => {
+    if (node.type.name === 'signatureBlock' || node.attrs['data-signature-block']) start = null;
+    if (node.attrs.replyQuoteStart) start = pos;
+    else if (start !== null && (node.type.name === 'quotedHtml' || node.type.name === 'blockquote')) {
+      if (node.textContent.trim() || String(node.attrs.html ?? '').trim()) {
+        ranges.push({ from: start, to: pos + node.nodeSize });
+      }
+      start = null;
+    } else if (start !== null) {
+      // Do not hide unrelated authored blocks while searching for a quote.
+      start = null;
+    }
+  });
+  return ranges;
+}
+
+/** Visibility is a view decoration, never a document edit or an undo step. */
+export const ReplyQuoteCollapse = Extension.create<{ show: string; hide: string }>({
+  name: 'replyQuoteCollapse',
+
+  addOptions() {
+    return { show: 'Show quoted text', hide: 'Hide quoted text' };
+  },
+
+  addGlobalAttributes() {
+    return [{
+      types: ['paragraph', 'heading', 'table', 'bulletList', 'orderedList', 'codeBlock', 'blockquote'],
+      attributes: {
+        replyQuoteStart: {
+          default: false,
+          parseHTML: (el) => el.getAttribute(START_ATTRIBUTE) === 'true',
+          renderHTML: (attrs) => attrs.replyQuoteStart ? { [START_ATTRIBUTE]: 'true' } : {},
+        },
+      },
+    }];
+  },
+
+  addProseMirrorPlugins() {
+    const labels = this.options;
+    return [new Plugin<QuoteState>({
+      key: quoteKey,
+      state: {
+        init: () => ({ expanded: new Set<number>() }),
+        apply: (tr, previous) => {
+          const expanded = new Set<number>();
+          for (const pos of previous.expanded) {
+            const mapped = tr.mapping.mapResult(pos);
+            if (!mapped.deleted) expanded.add(mapped.pos);
+          }
+          const toggle = tr.getMeta(quoteKey) as { from: number; expanded: boolean } | undefined;
+          if (toggle) {
+            if (toggle.expanded) expanded.add(toggle.from);
+            else expanded.delete(toggle.from);
+          } else if (tr.selectionSet) {
+            // Arrow keys, Find and editor commands must not leave the caret
+            // inside invisible text. Revealing it changes no message content.
+            for (const range of quoteRanges(tr.doc)) {
+              if (tr.selection.from < range.to && tr.selection.to > range.from) expanded.add(range.from);
+            }
+          }
+          return { expanded };
+        },
+      },
+      props: {
+        decorations(state) {
+          const expanded = quoteKey.getState(state)?.expanded ?? new Set<number>();
+          const decorations: Decoration[] = [];
+          for (const range of quoteRanges(state.doc)) {
+            const open = expanded.has(range.from);
+            decorations.push(Decoration.widget(range.from, (view) => {
+              const button = document.createElement('button');
+              button.type = 'button';
+              button.textContent = '•••';
+              button.className = 'my-1 inline-block cursor-pointer rounded-full bg-foreground/10 px-3 py-[3px] text-[11px] leading-none tracking-[2px] text-muted-foreground hover:bg-foreground/20 hover:text-foreground';
+              button.title = open ? labels.hide : labels.show;
+              button.setAttribute('aria-label', button.title);
+              button.setAttribute('aria-expanded', String(open));
+              button.addEventListener('click', () => {
+                const tr = view.state.tr.setMeta(quoteKey, { from: range.from, expanded: !open });
+                if (open) tr.setSelection(Selection.near(tr.doc.resolve(range.from), -1));
+                const restoreFocus = document.activeElement === button;
+                view.dispatch(tr);
+                if (restoreFocus) {
+                  const toggles = view.dom.querySelectorAll<HTMLButtonElement>('[data-reply-quote-toggle]');
+                  toggles.forEach((toggle) => {
+                    if (Number(toggle.dataset.replyQuoteToggle) === range.from) toggle.focus();
+                  });
+                }
+              });
+              button.dataset.replyQuoteToggle = String(range.from);
+              return button;
+            }, { key: `reply-quote-${range.from}-${open}`, side: -1, stopEvent: () => true }));
+            if (!open) {
+              state.doc.nodesBetween(range.from, range.to, (node, pos, parent) => {
+                if (parent === state.doc) {
+                  decorations.push(Decoration.node(pos, pos + node.nodeSize, { 'data-reply-quote-collapsed': 'true' }));
+                }
+                return false;
+              });
+            }
+          }
+          return DecorationSet.create(state.doc, decorations);
+        },
+      },
+    })];
+  },
+});
diff --git a/components/email/rich-text-editor.tsx b/components/email/rich-text-editor.tsx
index f462c9568..321f1a618 100644
--- a/components/email/rich-text-editor.tsx
+++ b/components/email/rich-text-editor.tsx
@@ -22,6 +22,7 @@ import { Table } from "@tiptap/extension-table";
 import { TableRow } from "@tiptap/extension-table-row";
 import { TableHeader } from "@tiptap/extension-table-header";
 import { TableCell } from "@tiptap/extension-table-cell";
+import { ReplyQuoteCollapse } from "@/components/email/reply-quote-collapse";
 import { QuotedHtml, serializeEditorContent } from "@/components/email/quoted-html";
 import { keepLoadedParagraphSpacing, paragraphStyleWithoutSpacing, trailingParagraphBreakRule } from "@/components/email/paragraph-breaks";
 import { SignatureBlock } from "@/components/email/signature-block";
@@ -225,6 +226,7 @@ export function RichTextEditor({
 }: RichTextEditorProps) {
   const rtlEditingSupport = useSettingsStore((st) => st.rtlEditingSupport);
   const tComposer = useTranslations("email_composer");
+  const tQuote = useTranslations("email_viewer");
   const onImageUploadRef = React.useRef(onImageUpload);
   onImageUploadRef.current = onImageUpload;
   const onEditorReadyRef = React.useRef(onEditorReady);
@@ -287,6 +289,7 @@ export function RichTextEditor({
       // Quoted/forwarded original email body - held verbatim as an atomic
       // node so layout-heavy HTML survives 1:1 (see quoted-html.ts).
       QuotedHtml,
+      ReplyQuoteCollapse.configure({ show: tQuote("show_quoted_text"), hide: tQuote("hide_quoted_text") }),
       // Identity signature - held verbatim as a non-editable atomic node so
       // rich/branded signatures keep their inline styling in the editor and
       // in the sent mail (see signature-block.ts). Double-click unlocks it