I produced a quick XForm to demonstrate how to do mouse handling. You can find it here: http://www.cwi.nl/~steven/forms/mouse.xml
Try clicking, double clicking, mouse wheel moves. I commented out mouse-move events, since so many of them are generated.
You can also see shift/alt/ctrl/meta keys working on mouse-down events (they work on other events, but I only show them on mouse-down).