flutter: disconnect connections when disposing group

src/flutter/dart/lib/HasConnections.dart

@@ -0,0 +1,23 @@
+/*
+  This file is part of KDDockWidgets.
+
+  SPDX-FileCopyrightText: 2025 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+  Author: Sérgio Martins <[email protected]>
+
+  SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+
+  Contact KDAB at <[email protected]> for commercial licensing options.
+*/
+
+import 'package:signals_slots/signals_slots.dart';
+
+mixin HasConnections {
+  final List<Connection> connections = [];
+  void connect(var signal, action) {
+    connections.add(signal.connect(action));
+  }
+
+  void disconnect() {
+    for (var con in connections) con.disconnect();
+  }
+}

src/flutter/dart/lib/widgets/GroupWidget.dart

@@ -9,13 +9,15 @@
   Contact KDAB at <[email protected]> for commercial licensing options.
 */
 
+import 'package:KDDockWidgets/HasConnections.dart';
 import 'package:KDDockWidgets/KDDockWidgets.dart';
 import 'package:KDDockWidgets/widgets/PositionedWidget.dart';
 import 'package:KDDockWidgets/widgets/TabBarWidget.dart';
 import 'package:KDDockWidgets/widgets/TitleBarWidget.dart';
 import 'package:KDDockWidgets/widgets/DockWidget.dart';
 
 import 'package:flutter/material.dart';
+import 'package:signals_slots/signals_slots.dart';
 
 class GroupWidget extends PositionedWidget {
   final Group group;
@@ -27,18 +29,25 @@ class GroupWidget extends PositionedWidget {
   }
 }
 
-class GroupWidgetState extends PositionedWidgetState {
+class GroupWidgetState extends PositionedWidgetState with HasConnections {
   final Group group;
+
   GroupWidgetState(this.group) : super(group) {
-    group.changed.connect(() {
+    connect(group.changed, () {
       setState(() {});
     });
 
-    group.titleChanged.connect(() {
+    connect(group.titleChanged, () {
       setState(() {});
     });
   }
 
+  @override
+  void dispose() {
+    disconnect();
+    super.dispose();
+  }
+
   @override
   Widget buildContents(BuildContext ctx) {
     final titleBarWidget = TitleBarWidget(group.titlebar);