Which GUI designer to choose?

Vaclav, thank you for this clarification.

···

Krjukov Victor wrote:
> a shortcoming of XRCed, I've manually edited the XRC file and add
> this parameter to some sizer, than I tried to use it via the same
> statement sizer = XRCCTRL(frame, "MainSizer")
> but that wasn't work

That's expected. Sizers are not widgets (or "real objects") and they
don't have name in wxWindows. XRCCTRL (meaning "XRC control") uses
names associated with wxWindow objects and because sizers are
anonymous and not windows at all, it can't find them.

> sizer = frame.GetSizer()

That's correct.

Regards,
Vaclav