'''watanabe''' found what is most likely the cause of the weird disappearing message view which occurred seemingly randomly.. with increased occurrence in 10.5 (probably from different handling of nil messaging).
accountSelectionView is set to nil after the first message is sent. At that point, calling [accountSelectionView frame] returns nil... and [accountSelectionView frame].size.height is not necessarily 0 but rather unstable.
This is basically his patch; thanks!
Fixes #5795
git-svn-id: svn://svn.adiumx.com/adium/branches/adium-1.0@18615 1c916fce-81e2-0310-a464-8ca513f45935