Custom context menu - C#

Matt C

I’m new to NPP plugin develoment. I’m using C#. A few questions:

I saw some comments online talking about overriding the context menu with a custom one. I’d like to bring up a custom context menu with commands for my plugin whenever a file of my file type is active?
Is there a way to disable menu items in the plugin menu and the default context menu? So when my file type is not the active file type/tab I do not wish my plugin command menu items to be enabled.

Thanks