Network: Set unselected edges to black.

src/View/Network/GraphWidget.py

@@ -174,7 +174,8 @@ class EdgeItem(QGraphicsItem):
             return
 
         # Select color
-        color = Qt.darkBlue
+        # color = Qt.darkBlue
+        color = Qt.black
         if self.graph.selected_item() == self:
             color = Qt.red
         elif self.graph.current_edge() == self: