(me again... logged in now :-) )

For the record/from the CB: the input device in use actually has 4 (buttons?): left single, left double, Rx1, Rx2; so there will be a fixed double-click timeout. Since this is for Win32, something of the nature of a main loop timer or Tk timeout like the above (probably invalid/nasty) pseudocode might be The Right Thing...

The Tk functions you need seem to be $timeout = Tk->after (time, \&sub); and Tk->after(cancel=>$timeout); which I found in libwww-perl archives.

Hope this helps!