Updated so it is only left mouse click that can open using the double click

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/MaterialNodeView.cs

 
         void OnSubGraphDoubleClick(MouseDownEvent evt)
         {
-            if (evt.clickCount == 2)
+            if (evt.clickCount == 2 && evt.button == 0)
             {
                 SubGraphNode subgraphNode = node as SubGraphNode;