Happens to me as well whenever there is precipitation. I normally carry a bottle of water with me and just pour some over the part where the door and the window meet. Frees things up quite nicely.
2011 VW GTI 4dr-6mt-Sunroof-Nav-Xenons
08 335i AW/CR/Poplar 6mt-ZSP-ZPP-ZCW-iPod-iDrive-PDC-Style 230s w/FK 452-Dinan LSD