possibly... every time i try to do something simple i find it's like 4 times harder than i thought. if you find any documentation on how to draw on those windows, let me know. chances are that the desktop panels aren't individual windows though. may be some trick to draw on them still.
i got some really bad code written that just closes conky instantly if you click in the top right area (x>750 && y <50) if in fullscreen mode only. well, it's the best simple solution i could come up with. x11 / xlib has no simple way to detect a double click of course.