fix: do not recreate the toolbar when the selection not changed (#1086)

lib/src/editor/toolbar/desktop/floating_toolbar.dart

@@ -75,6 +75,7 @@ class _FloatingToolbarState extends State<FloatingToolbar>
   late Brightness brightness = Theme.of(context).brightness;
 
   bool hasMetricsChanged = false;
+  Selection? lastSelection;
 
   @override
   void initState() {
@@ -82,6 +83,7 @@ class _FloatingToolbarState extends State<FloatingToolbar>
 
     WidgetsBinding.instance.addObserver(this);
     editorState.selectionNotifier.addListener(_onSelectionChanged);
+    lastSelection = editorState.selection;
     widget.editorScrollController.offsetNotifier.addListener(
       _onScrollPositionChanged,
     );
@@ -133,6 +135,8 @@ class _FloatingToolbarState extends State<FloatingToolbar>
   void _onSelectionChanged() {
     final selection = editorState.selection;
     final selectionType = editorState.selectionType;
+    if (lastSelection == selection) return;
+    lastSelection = selection;
 
     if (selection == null ||
         selection.isCollapsed ||

lib/src/editor/toolbar/desktop/floating_toolbar_widget.dart

@@ -54,6 +54,32 @@ class FloatingToolbarWidget extends StatefulWidget {
 }
 
 class _FloatingToolbarWidgetState extends State<FloatingToolbarWidget> {
+  EditorState get editorState => widget.editorState;
+  PropertyValueNotifier<Selection?> get selectionNotifier =>
+      editorState.selectionNotifier;
+
+  @override
+  void initState() {
+    super.initState();
+    selectionNotifier.addListener(_onSelectionChanged);
+  }
+
+  @override
+  void didUpdateWidget(FloatingToolbarWidget oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (widget.editorState != oldWidget.editorState) {
+      oldWidget.editorState.selectionNotifier
+          .removeListener(_onSelectionChanged);
+      selectionNotifier.addListener(_onSelectionChanged);
+    }
+  }
+
+  @override
+  void dispose() {
+    selectionNotifier.removeListener(_onSelectionChanged);
+    super.dispose();
+  }
+
   @override
   Widget build(BuildContext context) {
     var activeItems = _computeActiveItems();
@@ -97,6 +123,10 @@ class _FloatingToolbarWidgetState extends State<FloatingToolbarWidget> {
     );
   }
 
+  void _onSelectionChanged() {
+    if (mounted) setState(() {});
+  }
+
   Iterable<ToolbarItem> _computeActiveItems() {
     final activeItems = widget.items
         .where((e) => e.isActive?.call(widget.editorState) ?? false)