http://bugs.winehq.org/show_bug.cgi?id=29780
--- Comment #2 from Nikolay Sivov bunglehead@gmail.com 2012-02-09 00:50:06 CST --- Actually this is not a regression in Toolbar itself, but a problem with Rebar control that hosts it - band rectangle stays empty so WM_ERASEBKGND forwarded to Rebar by transparent Toolbar fails to fill properly.