QmlDesigner: fix for QTime

We have to call start() for QTime.
Calling elapsed() without calling start before
was never defined.

Change-Id: I229b3cbb30a2b3e5e98fdb05736ee0f37ae42c38
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>

src/plugins/qmldesigner/components/formeditor/formeditorscene.cpp

@@ -270,9 +270,16 @@ void FormEditorScene::mousePressEvent(QGraphicsSceneMouseEvent *event)
     }
 }
 
+static QTime staticTimer()
+{
+    QTime timer;
+    timer.start();
+    return timer;
+}
+
 void FormEditorScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
 {
-    static QTime time;
+    static QTime time = staticTimer();
 
     if (time.elapsed() > 30) {
         time.restart();