rear window leaking

I was wondering if anyone else had this problem in their f-150's I think they had a lot of problems with them and was wondering what the part was called that fixes it?

the black trim around the rear window is what's letting water in go down to the ur local Ford parts department and they should have that frame in stock.. it costs about 60.00 bucks

yeah, this guy i know had problems with his too but he never figured out what to do. sucks that u gotta spend money to fix their problem though