Based on a patch by Dan Kegel.

All that matters is that the real type is a user defined type (e.g.
structure, class, or union), so I used types_get_real_type instead of
types_get_info to avoid issues with typedefs.

Tests show that the edit control uses a dialog mode after receiving 
WM_GETDLGCODE message and it doesn't depend on whether the edit control 
has a parent window.