Ok, I’ve reviewed your example in detail.
But I have the following problem.
I use the GoGeneralNode in my application, because I need the “Left” and “Right”-Ports.
But the GoGeneralNode doesn’t trigger the “public override void AddSelectionHandles(GoSelection sel, GoObject selectedObj)”-Method.
If I see right the GoBoxNode (as used in your example) does not support the additional ports.
I wouldn’t like to draw the additional ports by my self, because they can be moved (change order) in my application and that could be very complicated I think.