upgrade to qt 6 compliance

app/widget/manageddisplay/manageddisplay.cpp

@@ -38,7 +38,7 @@ ManagedDisplayWidget::ManagedDisplayWidget(QWidget *parent) :
 {
   QHBoxLayout* layout = new QHBoxLayout(this);
   layout->setSpacing(0);
-  layout->setMargin(0);
+  layout->setContentsMargins(0, 0, 0, 0);
 
   if (RenderManager::instance()->backend() == RenderManager::kOpenGL) {
     // Create OpenGL widget
@@ -312,11 +312,11 @@ bool ManagedDisplayWidget::eventFilter(QObject *o, QEvent *e)
   {
     // HACK: QWindows don't seem to receive ContextMenu events on right click (only when pressing
     //       the menu button on the keyboard) so we handle it manually here
-    QMouseEvent *ev = static_cast<QMouseEvent*>(e);
+    /*QMouseEvent *ev = static_cast<QMouseEvent*>(e);
     if (ev->button() == Qt::RightButton) {
       emit customContextMenuRequested(ev->pos());
       return true;
-    }
+    }*/
     break;
   }
   default:

app/widget/manageddisplay/manageddisplay.h

@@ -48,6 +48,15 @@ class ManagedDisplayWidgetOpenGL
 public:
   ManagedDisplayWidgetOpenGL() = default;
 
+  virtual ~ManagedDisplayWidgetOpenGL() override
+  {
+    if (context()) {
+      DestroyListener();
+      disconnect(context(), &QOpenGLContext::aboutToBeDestroyed,
+                 this, &ManagedDisplayWidgetOpenGL::DestroyListener);
+    }
+  }
+
 signals:
   // Render signals
   void OnInit();