QmlDesigner: Fix translation issue

Change-Id: Ia7858ef275fdee8a2721fb63e772b27097e0c19e
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/plugins/qmldesigner/components/navigator/navigatortreeview.h

@@ -32,6 +32,8 @@ namespace QmlDesigner {
 
 class NavigatorTreeView : public QTreeView
 {
+    Q_OBJECT
+
 public:
     NavigatorTreeView(QWidget *parent = 0);
     static void drawSelectionBackground(QPainter *painter, const QStyleOption &option);