WoW:API TurnOrActionStop
This is triggered by releasing the right mousebutton. If keystate up is true of that button then this fires. Anything contained within this function will then also fire.
Additions can be made to this functions via temporary override, as follows ...
function AddOn_OnLoad() Override_TurnOrActionStop=TurnOrActionStop TurnOrActionStop=Override end
function Override() [Do stuff.] Override_TurnOrActionStop(arg1,arg2,arg3,arg4,arg5,arg6,arg7,arg8,arg9) end
So we could add the notice; "Right mouse button released!" into the function.
function Override() DEFAULT_CHAT_FRAME:AddMessage("Right mouse button is down!") Override_TurnOrActionStop(arg1,arg2,arg3,arg4,arg5,arg6,arg7,arg8,arg9) end