diff --git a/frontend/src/components/input/editor/mention/mentionSuggestion.ts b/frontend/src/components/input/editor/mention/mentionSuggestion.ts
index 0aaf756a8..1afd2f66a 100644
--- a/frontend/src/components/input/editor/mention/mentionSuggestion.ts
+++ b/frontend/src/components/input/editor/mention/mentionSuggestion.ts
@@ -3,6 +3,7 @@ import { computePosition, flip, shift, offset, autoUpdate } from '@floating-ui/d
 import type { Editor } from '@tiptap/core'
 
 import MentionList from './MentionList.vue'
+import { getPopupContainer } from '../popupContainer'
 import ProjectUserService from '@/services/projectUsers'
 import { fetchAvatarBlobUrl, getDisplayName } from '@/models/user'
 import type { IUser } from '@/modelTypes/IUser'
@@ -113,7 +114,8 @@ export default function mentionSuggestionSetup(projectId: number) {
 					popupElement.style.left = '0'
 					popupElement.style.zIndex = '4700'
 					popupElement.appendChild(component.element!)
-					document.body.appendChild(popupElement)					// Update virtual reference
+					getPopupContainer(props.editor).appendChild(popupElement)
+					// Update virtual reference
 					const rect = props.clientRect()
 					if (rect) {
 						virtualReference.getBoundingClientRect = () => rect
@@ -179,7 +181,7 @@ export default function mentionSuggestionSetup(projectId: number) {
 						cleanupFloating()
 					}
 					if (popupElement) {
-						document.body.removeChild(popupElement)
+						popupElement.remove()
 						popupElement = null
 					}
 					component.destroy()
diff --git a/frontend/src/components/input/editor/popupContainer.ts b/frontend/src/components/input/editor/popupContainer.ts
new file mode 100644
index 000000000..92679d936
--- /dev/null
+++ b/frontend/src/components/input/editor/popupContainer.ts
@@ -0,0 +1,11 @@
+import type {Editor} from '@tiptap/core'
+
+// Native <dialog> elements opened with showModal() render in the browser's
+// top-layer, so popups appended to document.body end up visually behind them
+// regardless of z-index. Appending to the open dialog itself lifts the popup
+// into the same top-layer stacking context.
+export function getPopupContainer(editor?: Editor): HTMLElement {
+	const editorEl = editor?.view?.dom as HTMLElement | undefined
+	const dialog = editorEl?.closest('dialog[open]') as HTMLElement | null
+	return dialog ?? document.body
+}
diff --git a/frontend/src/components/input/editor/suggestion.ts b/frontend/src/components/input/editor/suggestion.ts
index 151afc7f7..55146c34f 100644
--- a/frontend/src/components/input/editor/suggestion.ts
+++ b/frontend/src/components/input/editor/suggestion.ts
@@ -3,6 +3,7 @@ import {VueRenderer} from '@tiptap/vue-3'
 import {computePosition, flip, shift, offset, autoUpdate} from '@floating-ui/dom'
 
 import CommandsList from './CommandsList.vue'
+import {getPopupContainer} from './popupContainer'
 
 type TranslateFunction = (key: string) => string
 
@@ -206,7 +207,7 @@ export default function suggestionSetup(t: TranslateFunction) {
 					popupElement.style.left = '0'
 					popupElement.style.zIndex = '4700'
 					popupElement.appendChild(component.element!)
-					document.body.appendChild(popupElement)
+					getPopupContainer(props.editor).appendChild(popupElement)
 
 					// Update virtual reference
 					const rect = props.clientRect()
@@ -266,7 +267,7 @@ export default function suggestionSetup(t: TranslateFunction) {
 						cleanupFloating()
 					}
 					if (popupElement) {
-						document.body.removeChild(popupElement)
+						popupElement.remove()
 						popupElement = null
 					}
 					component.destroy()