http://bugs.winehq.org/show_bug.cgi?id=6715
--- Comment #6 from Stephan Sokolow from_wine_bugzilla@ssokolow.com 2008-04-05 20:14:13 --- The problem is lessened (the full pink background doesn't seem to appear anymore) but the pink border around the letters (The attachment titled "The less common state for text to be rendered in") still remains and the text is completely pink when scrolling back to prior conversation elements.
As far as I can guess from what I remember of using them on real Windows, Wine is giving it 1-bit transparency when it's asking for an alpha channel. (The scrollback text should be ghostly rather than pink and the pink border on all text should be anti-aliasing)