diff --git a/flutter/lib/models/state_model.dart b/flutter/lib/models/state_model.dart
index 82176c1a0..4afd77db2 100644
--- a/flutter/lib/models/state_model.dart
+++ b/flutter/lib/models/state_model.dart
@@ -11,7 +11,7 @@ enum SvcStatus { notReady, connecting, ready }
 class StateGlobal {
   int _windowId = -1;
   bool grabKeyboard = false;
-  RxBool _fullscreen = false.obs;
+  final RxBool _fullscreen = false.obs;
   bool _isMinimized = false;
   final RxBool isMaximized = false.obs;
   final RxBool _showTabBar = true.obs;