diff --git a/lib/view/pages/talk/widgets/chat_textfield.dart b/lib/view/pages/talk/widgets/chat_textfield.dart
index 16ef6fc..1024159 100644
--- a/lib/view/pages/talk/widgets/chat_textfield.dart
+++ b/lib/view/pages/talk/widgets/chat_textfield.dart
@@ -114,7 +114,15 @@ class _ChatTextfieldState extends State<ChatTextfield> {
 
   @override
   void dispose() {
-    downloadChipBottomObstruction.value = 0;
+    // Clear the published bar height only after this unmount completes. Setting
+    // the shared notifier synchronously here fires its listener (the download
+    // tray's AnimatedBuilder → setState) while the element tree is locked during
+    // teardown, throwing "setState() called when widget tree was locked".
+    // Running it at the end of the frame lets the reset land once the tree is
+    // writable again; a newly opened chat re-publishes its own height afterwards.
+    WidgetsBinding.instance.addPostFrameCallback(
+      (_) => downloadChipBottomObstruction.value = 0,
+    );
     _sendController.dispose();
     _focusNode.dispose();
     super.dispose();