http://bugs.winehq.org/show_bug.cgi?id=24823
--- Comment #10 from Nikolay Sivov bunglehead@gmail.com 2011-07-15 01:34:27 CDT --- After some testing I see now that uxtheme uses handles, not plain pointers. So valid HTHEME looks like 0x00010001,0x00020001 (or 2 at least significant position). That's why it's resistant to invalid handles like 0x1.