Is it possible to add buttons to the right click menu below?
Did you found a solution scottMHA?
Unfortunately not so far, still on the hunt as and when time allows.
Use
CommandBarContextPopup ctxPopup = UIEnvironment.GetContextMenu(typeof(Part));
to access the menu.
Thank you for the answer. Now that I found some time to try this I failed 
VS doesn’t know Part in context of the typeof expression. Do you have a short simple example how I can add buttons with my custom code to different menues?
My goal is to add a button to the menues of paths, robtargets and workobjects. If you could show me an example of one of them I would really thank you for that.