http://bugs.winehq.org/show_bug.cgi?id=6842
--- Comment #9 from Dmitry Timoshkov dmitry@codeweavers.com 2008-01-07 23:30:39 --- (In reply to comment #8)
This isn't a performance issue. My code will have lower performance because it is more complex than drawing a rectangle. The bug is that there are color combinations that the current Rectangle() based code will not produce a clear focus rectangle. My code duplicates the Microsoft method which ensures that a clear focus rectangle will be drawn on any color combination no matter how bad it actually looks.
Then just create a patch without caching (to make the code simpler for review) and either attach it here or send to wine-patches.