Which OS are you on?

Vista Basic 64-bit

Such a problem is also evident in Windows Defender: Its main window is getting smaller while being active whenever one mouseovers one of the top row links.

I have also had a simuliar problem as this with IMVU.   I can't have windowblinds up and still be able to resize the room window. (  It's not easy chatting with your friends when you're using avatars that can move around and chat bubbles(that move with them) in a small window!   I have found along the way that if I apply the Classic or WindowsXP default skin, I can resize the window just fine.   Yeah, I know it sucks changing over, but I think some sites just don't like to be skinned.   Hope this helps. If anyone has a better way of doing this, I would be interested in knowing. If you have time PM me.   

Merry Christmas everybody!!     

This problem also occurs with PowerArchiver 2007 whose size increases on every open and which isn't get skinned as well.

These problems still occur in the paid version. WLM and PA are not getting skinned despite the option to skin non-theme-aware problems has been chosen.