Process Mac toolbar toggling event

src/GUI.cpp

@@ -624,7 +624,8 @@ void GUI::on_actionCreate_torrent_triggered() {
 }
 
 bool GUI::event(QEvent * e) {
-  if(e->type() == QEvent::WindowStateChange) {
+  switch(e->type()) {
+  case QEvent::WindowStateChange: {
       qDebug("Window change event");
       //Now check to see if the window is minimised
       if(isMinimized()) {
@@ -639,6 +640,16 @@ bool GUI::event(QEvent * e) {
           }
         }
       }
+      break;
+    }
+#ifdef Q_WS_MAC
+  case QEvent::ToolBarChange: {
+      actionTop_tool_bar->setChecked(toolBar->isVisible());
+      break;
+    }
+#endif
+  default:
+    break;
   }
   return QMainWindow::event(e);
 }