Simlar to me, i rub mine with WD40. Make them look all clean and new too.Used to have same with mine. I just wipe some white grease around the window and door seals and that stops it freezing and sticking.
However I have no idea if the grease damages the seals in the long term so may be worth checking first.
Worked in Germany few years back when it was -10!
In that case I don't think you can stop them...Thanks for the info folks some good laughs there as well, I had tried the water on seals job but they still wouldn't budge, also my mirror folds automatically so how can I stop it doing that in the winter ? I have ones of those modules wired in to the windows