diff --git a/src/editor/plugins/mark-popover.ts b/src/editor/plugins/mark-popover.ts
index 7bb4e581..562deb9d 100644
--- a/src/editor/plugins/mark-popover.ts
+++ b/src/editor/plugins/mark-popover.ts
@@ -1215,6 +1215,10 @@ class MarkPopoverController {
   }
 
   private renderSuggestion(mark: Mark): void {
+    if (mark.kind === 'flagged') {
+      this.renderFlag(mark);
+      return;
+    }
     this.popover.innerHTML = '';
 
     const header = document.createElement('div');
@@ -1286,6 +1290,45 @@ class MarkPopoverController {
     this.popover.appendChild(actions);
   }
 
+  private renderFlag(mark: Mark): void {
+    this.popover.innerHTML = '';
+
+    const header = document.createElement('div');
+    header.className = 'mark-popover-header';
+    header.textContent = `Flagged by ${getActorName(mark.by)}`;
+
+    const body = document.createElement('div');
+    body.className = 'mark-popover-body';
+    const note = (mark.data as { note?: string } | undefined)?.note;
+    body.textContent = note || mark.quote || '';
+
+    const actions = document.createElement('div');
+    actions.className = 'mark-popover-actions';
+
+    if (canCommentInRuntime()) {
+      const removeButton = document.createElement('button');
+      removeButton.type = 'button';
+      removeButton.textContent = 'Remove flag';
+      installTouchSafeButton(removeButton, () => {
+        deleteMark(this.view, mark.id);
+        this.close();
+      });
+      actions.appendChild(removeButton);
+    }
+
+    const closeButton = document.createElement('button');
+    closeButton.type = 'button';
+    closeButton.textContent = 'Close';
+    installTouchSafeButton(closeButton, () => {
+      this.close();
+    });
+    actions.appendChild(closeButton);
+
+    this.popover.appendChild(header);
+    this.popover.appendChild(body);
+    this.popover.appendChild(actions);
+  }
+
   private cacheActionRange(): void {
     const { from, to } = this.view.state.selection;
     if (from === to) return;
diff --git a/src/editor/plugins/marks.ts b/src/editor/plugins/marks.ts
index 910604cb..1356af9b 100644
--- a/src/editor/plugins/marks.ts
+++ b/src/editor/plugins/marks.ts
@@ -3110,9 +3110,14 @@ function createDecorations(
     switch (mark.kind) {
       case 'authored':
       case 'approved':
-      case 'flagged':
         continue;
 
+      case 'flagged': {
+        style = STYLES.flagged;
+        cssClass = `mark-flagged ${isActive ? 'mark-active' : ''}`;
+        break;
+      }
+
       case 'comment': {
         const data = mark.data as CommentData;
         if (data?.resolved) continue;
@@ -3223,6 +3228,15 @@ function injectGlowStyles(): void {
       100% { box-shadow: none; }
     }
 
+    /* Flag glow (dusty rose, box-shadow only so the flag background persists) */
+    .mark-flagged.proof-mark-new {
+      animation-name: proof-flag-glow;
+    }
+    @keyframes proof-flag-glow {
+      0% { box-shadow: 0 0 8px rgba(252, 165, 165, 0.8); }
+      100% { box-shadow: none; }
+    }
+
     /* Refresh transition animations */
     .proof-refreshing { opacity: 0.3; transition: opacity 200ms ease-out; }
     .proof-refreshed { opacity: 1; transition: opacity 300ms ease-in; }