Problem: Creation of a modless CDialog in a thread.

[Cariboo42]

Maybe this will help: http://support.microsoft.com/kb/183116

Thanks. It helps to understand how dialog message pump works and the problems inherent to such design when using in threads. But this concerns essentially modal dialogs. IMO, it should work with modless dialogs, but what I also understand is that modless CDialog creation is not multi-thread safe regarding to PostThreadMessage.

IMO this is a bad design. Multi-threaded code is hard to debug and it's easy to introduce errors

Indeed, it seems to be a bad design to create windows in separate threads. So I’ll redesign my application that way.
But I do not agree with the fact that MT programming is hard to debug. It’s like everything else: It requires being rigorous.