frozen window on 06 318ci convertible

[red soft top]

(apologies if i do anything wrong... im new!)

two days ago i went to my car, which i have to park on the road, and it was more difficult to open the door. then realised the window had not moved down the small amount it should do for it to open. needless to say i could not shut it until i had warmed the car up and window had unfrozen! i noticed it didnt sound like it had as good a seal either.

my question is... how can i prevent this from happening? and will putting hood down and then up again reinforce the seal properly (obviously not until it has got a bit warmer and snow has departed!)

would appreciate any suggestions as i dont want to damage the window or door but what a nuisance that it does this!
many thanks