What is the best way offered by the Rhino SDK for creating contextual menus.
This involves first managing real-time object selection events in the Rhino window
(click, double-click, right-clicking)
and displaying pop-up menus
(like in Grasshopper or you can fill in dimensional values in a contextual menu on the inputs of the components)
The Rhino SDK does not provide support for object context picking. Thus, anything you do will be custom.
You might start with the MouseCallback class and see how far you get.
https://developer.rhino3d.com/5/api/RhinoCommonWin/html/T_Rhino_UI_MouseCallback.htm
– Dale