Different actions for the menu "pump" callback
A menu has been started (nothing passed)
A menu is about to be displayed (param1=client, param2=MenuPanel Handle)
An item was selected (param1=client, param2=item)
The menu was cancelled (param1=client, param2=reason)
A menu display has fully ended. param1 is the MenuEnd reason, and if it's MenuEnd_Cancelled, then param2 is the MenuCancel reason from MenuAction_Cancel.
(VOTE ONLY): A vote sequence has succeeded (param1=chosen item) This is not called if SetVoteResultCallback has been used on the menu.
(VOTE ONLY): A vote sequence has been cancelled (param1=reason)
An item is being drawn; return the new style (param1=client, param2=item)