iPhoto does not play videos anymore since Mavericks update!??

and the problem is merely in iphoto, not quicktime! the new quicktime can play the videos no problem - i copied the videos to an external harddrive and then opened them with the new quicktime and they play! they do not play in iphoto though when i just click them - like they used to do in all old iphotos. this is surely a flaw by apple that must be fixed!!!!

apart from all the other things that make me wish i could downgrade to lion............