There was a hook to allow you to use 2 button mice with plan9 which used (as I remember) the shift key to make button 3 bring up the menu normally used for button 2.
I cannot make this work any more but I have a usb mouse and keyboard, perhaps it was a feature of the PS2 mouse/keyboard drievr? Anyway, perhaps your keyboard is the problem, not sending a key-up event when you release the shift key somtimes? Just a guess. -Steve
