Sometimes on quite fast machine(Intel Core i7-2600@3.4GHz) with Win8 there's a little bit strange behavior: resize handle appears and disappears in way, distinct from one, observable on any other platform.
E.g. when user release LMB after resize it appears, disappears and then appears once again. And it takes less then 1s for all 3 steps.
It affects resize tests because Jemmy throws NPE while trying to handle such behavior. The only visible workaround is ugly -- just add Thread.sleep(1000).