network: Fix minor bug.

src/view/network/GraphWidget.py

@@ -271,6 +271,7 @@ class GraphWidget(QGraphicsView):
 
         self.m_origin_x = 0.0
         self.m_origin_y = 0.0
+        self.clicked = False
 
         scene = QGraphicsScene(self)
         scene.setItemIndexMethod(QGraphicsScene.NoIndex)
@@ -603,6 +604,7 @@ class GraphWidget(QGraphicsView):
 
     def mousePressEvent(self, event):
         pos = self.mapToScene(event.pos())
+        self.clicked = True
 
         # Move item and select edge item
         if self._state == "move":
@@ -649,6 +651,8 @@ class GraphWidget(QGraphicsView):
         super(GraphWidget, self).mousePressEvent(event)
 
     def mouseReleaseEvent(self, event):
+        self.clicked = False
+
         self.update()
         super(GraphWidget, self).mouseReleaseEvent(event)
 
@@ -666,7 +670,7 @@ class GraphWidget(QGraphicsView):
 
         if selectable_items:
             self.set_selected_item(selectable_items[0])
-        else:
+        elif self.clicked == False:
             self.set_selected_item(None)
 
         # Update temporary line