fix: keeps mouse region grab key on linux

flutter/lib/desktop/pages/remote_page.dart

@@ -128,21 +128,31 @@ class _RemotePageState extends State<RemotePage>
   @override
   void onWindowBlur() {
     super.onWindowBlur();
+    // On windows, we use `focus` way to handle keyboard better.
+    // Now on Linux, there's some rdev issues which will break the input.
+    // We disable the `focus` way for non-Windows temporarily.
+    if (Platform.isWindows) {
       _isWindowBlur = true;
-    // unfocus the key focus when the whole window is lost focus,
+      // unfocus the primary-focus when the whole window is lost focus,
       // and let OS to handle events instead.
       _rawKeyFocusNode.unfocus();
     }
+  }
 
   @override
   void onWindowFocus() {
     super.onWindowFocus();
+    // See [onWindowBlur].
+    if (Platform.isWindows) {
       _isWindowBlur = false;
     }
+  }
 
   @override
   void dispose() {
     debugPrint("REMOTE PAGE dispose ${widget.id}");
+    // ensure we leave this session, this is a double check
+    bind.sessionEnterOrLeave(id: widget.id, enter: false);
     DesktopMultiWindow.removeListener(this);
     _ffi.dialogManager.hideMobileActionsOverlay();
     _ffi.recordingModel.onClose();
@@ -175,6 +185,8 @@ class _RemotePageState extends State<RemotePage>
                       onFocusChange: (bool imageFocused) {
                         debugPrint(
                             "onFocusChange(window active:${!_isWindowBlur}) $imageFocused");
+                        // See [onWindowBlur].
+                        if (Platform.isWindows) {
                           if (_isWindowBlur) {
                             imageFocused = false;
                             Future.delayed(Duration.zero, () {
@@ -186,6 +198,7 @@ class _RemotePageState extends State<RemotePage>
                           } else {
                             _ffi.inputModel.enterOrLeave(false);
                           }
+                        }
                       },
                       inputModel: _ffi.inputModel,
                       child: getBodyForDesktop(context)));
@@ -221,6 +234,13 @@ class _RemotePageState extends State<RemotePage>
         //
       }
     }
+    // See [onWindowBlur].
+    if (!Platform.isWindows) {
+      if (!_rawKeyFocusNode.hasFocus) {
+        _rawKeyFocusNode.requestFocus();
+      }
+      bind.sessionEnterOrLeave(id: widget.id, enter: true);
+    }
   }
 
   void leaveView(PointerExitEvent evt) {
@@ -233,6 +253,10 @@ class _RemotePageState extends State<RemotePage>
         //
       }
     }
+    // See [onWindowBlur].
+    if (!Platform.isWindows) {
+      bind.sessionEnterOrLeave(id: widget.id, enter: false);
+    }
   }
 
   Widget getBodyForDesktop(BuildContext context) {