Adding macro to middle mouse button and Cascade menu

Hello Rhino Community
I was trying to make a usable user interface for the commands I have been writing in rhino plugin, I came across the following questions

  1. how do I add a macro to a middle mouse button action for a custom button buttons in the workspace editor.
  2. How do I add a cascade tab to a custom button with custom macros on the cascade list (eg. Macro 1,Macro 2, Macro 3) . would be great if you could add some examples.

Thanks in Advance

Hi Arjun - start here -