Well...

Sicne there is already a right click menu in the channel, right clicking and getting 2 popups wouldn't be good.

It's usually easier to use menu like I said and make your own commands that way.

Code:
menu channel {
  My Menu
  .Level One
  ..Level Two
  ...Level Three://echo -a Hi.
}


Yes, you can use dlls to do menus and popups and such. But often they really aren't needed.