nodeview: update positions correctly

app/widget/nodeview/nodeviewitem.h

@@ -40,8 +40,9 @@ class NodeViewEdge;
  *
  * To retrieve the NodeViewItem for a certain Node, use NodeView::NodeToUIObject().
  */
-class NodeViewItem : public QGraphicsRectItem
+class NodeViewItem : public QObject, public QGraphicsRectItem
 {
+  Q_OBJECT
 public:
   NodeViewItem(QGraphicsItem* parent = nullptr);
 
@@ -111,6 +112,9 @@ public:
 
   void SetHighlightedIndex(int index);
 
+signals:
+  void NodePositionChanged(const QPointF &pos);
+
 protected:
   virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = nullptr) override;
 
@@ -174,6 +178,8 @@ private:
 
   QPointF cached_node_pos_;
 
+  bool dont_signal_;
+
 };
 
 }