QmlDesigner: Disable TransitionEditorView when not visible

Change-Id: I76a1829dae18d651168f92558d65beb8b94f1f88
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmldesigner/components/transitioneditor/transitioneditorview.cpp

@@ -72,6 +72,10 @@ TransitionEditorView::~TransitionEditorView() = default;
 void TransitionEditorView::modelAttached(Model *model)
 {
     AbstractView::modelAttached(model);
+
+    if (!isEnabled())
+        return;
+
     if (m_transitionEditorWidget)
         m_transitionEditorWidget->init();
 }

src/plugins/qmldesigner/components/transitioneditor/transitioneditorwidget.cpp

@@ -385,10 +385,24 @@ void TransitionEditorWidget::setupScrollbar(int min, int max, int current)
 void TransitionEditorWidget::showEvent(QShowEvent *event)
 {
     Q_UNUSED(event)
+
+    m_transitionEditorView->setEnabled(true);
+
+    if (m_transitionEditorView->model())
+        init();
+
     graphicsScene()->setWidth(m_graphicsView->viewport()->width());
     graphicsScene()->invalidateLayout();
     graphicsScene()->invalidate();
     graphicsScene()->onShow();
+
+    QWidget::showEvent(event);
+}
+
+void TransitionEditorWidget::hideEvent(QHideEvent *event)
+{
+    m_transitionEditorView->setEnabled(false);
+    QWidget::hideEvent(event);
 }
 
 void TransitionEditorWidget::resizeEvent(QResizeEvent *event)

src/plugins/qmldesigner/components/transitioneditor/transitioneditorwidget.h

@@ -74,6 +74,7 @@ public slots:
 
 protected:
     void showEvent(QShowEvent *event) override;
+    void hideEvent(QHideEvent *event) override;
     void resizeEvent(QResizeEvent *event) override;
 
 private: