diff --git a/src/components/room/RoomChatPanel.tsx b/src/components/room/RoomChatPanel.tsx
index 94b18c4..fd1af43 100644
--- a/src/components/room/RoomChatPanel.tsx
+++ b/src/components/room/RoomChatPanel.tsx
@@ -83,7 +83,11 @@ const ChatInputArea = memo(function ChatInputArea({
 
   // Track DOM cursor offset → ms.cursorOffset on every render
   const prevCursorRef = useRef(ms.cursorOffset);
+  // Set when a deferred cursor update is scheduled; cleared when it fires.
+  // Prevents the tracking effect from overwriting a programmatically-set cursor.
+  const skipCursorTrackingRef = useRef(false);
   useEffect(() => {
+    if (skipCursorTrackingRef.current) return;
     const el = containerRef.current;
     if (!el) return;
     const sel = window.getSelection();
@@ -131,7 +135,9 @@ const ChatInputArea = memo(function ChatInputArea({
       const newCursorPos = startPos + 1 + category.length + 1;
       onDraftChangeRef.current(newValue);
       ms.setValue(newValue);
+      skipCursorTrackingRef.current = true;
       setTimeout(() => {
+        skipCursorTrackingRef.current = false;
         ms.setCursorOffset(newCursorPos);
         ms.setShowMentionPopover(!!newValue.substring(0, newCursorPos).match(/@([^:@\s]*)(:([^\s]*))?$/));
       }, 0);
@@ -249,8 +255,14 @@ const ChatInputArea = memo(function ChatInputArea({
               const newCursorPos = startPos + 1 + category.length + 1;
               onDraftChangeRef.current(newValue);
               ms.setValue(newValue);
-              // Defer cursor update until after DOM has flushed the new mention value
-              setTimeout(() => ms.setCursorOffset(newCursorPos), 0);
+              // Defer cursor update until after DOM has flushed the new mention value.
+              // Skip tracking effect during the flush window to avoid it overwriting
+              // the deferred cursor with the old DOM position.
+              skipCursorTrackingRef.current = true;
+              setTimeout(() => {
+                skipCursorTrackingRef.current = false;
+                ms.setCursorOffset(newCursorPos);
+              }, 0);
             }}
             suggestions={ms.suggestions}
             selectedIndex={ms.selectedIndex}