Just figured out why I was having trouble sometimes with check boxes on web-page forms in IE 6 in OS X on the Mac (just being specific). It turns out that if I move the mouse pointer off the checkbox too quickly the click doesn’t register. Apparently I need to have the mouse pointer on the checkbox when I click and I have to keep it there for some number of microsends until the click registers and the box becomes checked or un-. This is crazy! Clearly I tend to move much faster than that usually because (1) I was missing the box a lot this way and (2) I notice the lag now as I wait for the sluggish check to register. Bah!