Fix implementation

src/gui/MainWindow.cpp

@@ -1809,9 +1809,8 @@ void MainWindow::initViewMenu()
 
 #if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
 
-MainWindowEventFilter::MainWindowEventFilter(MainWindow* mainWindow)
-    : QObject(mainWindow)
-    , m_mainWindow(mainWindow)
+MainWindowEventFilter::MainWindowEventFilter(QObject* parent)
+    : QObject(parent)
 {
 }
 
@@ -1820,15 +1819,27 @@ MainWindowEventFilter::MainWindowEventFilter(MainWindow* mainWindow)
  */
 bool MainWindowEventFilter::eventFilter(QObject* watched, QEvent* event)
 {
-    if (!m_mainWindow) {
+    auto* mainWindow = getMainWindow();
+    if (!mainWindow || !mainWindow->m_ui) {
         return QObject::eventFilter(watched, event);
     }
 
-    if (watched == m_mainWindow->m_ui->menubar || watched == m_mainWindow->m_ui->toolBar
-        || watched == m_mainWindow->m_ui->tabWidget->tabBar()) {
-        if (event->type() == QEvent::MouseButtonPress) {
-            auto* window = qobject_cast<QWindow*>(m_mainWindow->windowHandle());
-            window->startSystemMove();
+    if (event->type() == QEvent::MouseButtonPress) {
+        if (watched == mainWindow->m_ui->menubar) {
+            mainWindow->windowHandle()->startSystemMove();
+            // Continue processing events, so menus keep working.
+            return false;
+        } else if (watched == mainWindow->m_ui->toolBar) {
+            if (!mainWindow->m_ui->toolBar->isMovable() || mainWindow->m_ui->toolBar->cursor() != Qt::SizeAllCursor) {
+                mainWindow->windowHandle()->startSystemMove();
+                return false;
+            }
+        } else if (watched == mainWindow->m_ui->tabWidget->tabBar()) {
+            auto* m = static_cast<QMouseEvent*>(event);
+            if (mainWindow->m_ui->tabWidget->tabBar()->tabAt(m->pos()) == -1) {
+                mainWindow->windowHandle()->startSystemMove();
+                return true;
+            }
         }
     }
 

src/gui/MainWindow.h

@@ -193,11 +193,8 @@ class MainWindowEventFilter : public QObject
     Q_OBJECT
 
 public:
-    explicit MainWindowEventFilter(MainWindow* mainWindow);
+    explicit MainWindowEventFilter(QObject* parent);
     bool eventFilter(QObject* watched, QEvent* event) override;
-
-private:
-    QPointer<MainWindow> m_mainWindow;
 };
 #endif