Hi!! This is wrong, 8^(
+ class.style |= CS_GLOBALCLASS; + class.hInstance = COMCTL32_hModule;
The point in THEMING_Initialize was to get the current global classes and make locals for each process. So that process could have it. Not the whole system!
Note from a msdn blog, "If you pass the CS_GLOBALCLASS flag when registering the class, then the window manager will ignore the instance handle when looking for your class. All of the USER32 classes are registered as global."
I spent a week now looking through it all, ReactOS is handling the class registration correctly. My best guess, if themes is active do as the original code had it before and use IsThemeActive like it is setup. Keep class.hInstance = COMCTL32_hModule; and don't use CS_GLOBALCLAS so you can find it again.
Thanks, James