Well i gotta tell you i was messing around with mine a few weeks ago when that spring flew of my window i did manage to find it but you know i spent about 4 hours trying to put it back in and you know what? i said screw it i put it in without the spring and i am sooo happy i did cuz that damn thing popping open was driving me nuts.
So anyway

just put it on without the spring... if that's the problem... hehe.