So that versioned window classes gets registered as well. Otherwise, comctl32 v6 fails to register its window classes when comctl32 v5 classes are still being used. This can happen, for example, when creating a window using comctl32 v5, then unload comctl32 v5 and not destroying the window, and then load comctl32 v6.
Is this still true? This shouldn't happen if things are working correctly.