How to determine which eclipse plugins are contributing to menus and toolbars and stop them

Question

I am creating an RCP app which uses a host of third-party plugins. Some of these plugins contribute menus, menu items, and toolbar buttons that I do not wish to display. How can

Answer 1

Alt + Shift + F2
then click some menu.
You can know contributor and menu URI.

Alt + Shift + F1 : inspect current active part and selection.
Alt + Shift + F3 : inspector contributor of Widget or item.

You needs plugin-spy plugin in runtime.