Since i have installed WLM 2009 final (14.0.8050.1202) i'm having this strange problem with the default skin: if I resize a conversation Window i get the standard Windows bar on the top instead of the skinned one, and all the "skin" doesn't work anymore (no animation when i hover a button, but they works if i click).
I have the same problem (the bar one) on the contact list but it seems to be permanent.
I'll post a couple of images to explain better:
Bugged Contact List skin (buttons works fine until i resize it):
Standard (working) conversation window skin:
Not working conversation window skin: