Rather than have everything in one big dialog, I'm looking at being able to display child dialogs for separate groups of controls. The idea is these are not free-floating child dialogs like floating toolbars, but would be shown with no title-bar, their position locked to the parent dialog... so as you drag the parent dialog any open child is dragged too.

NOTE: these child windows are not inside the parent dialog, they would typically be 'glued' to the edge of it.

In MFC/VC++ 2005, what's the best way to do this? For testing, I currently have a standard MFC Dialog-based app setup with CMainDlg, and I've then created a 'widget dialog' CWidgetDlg. So far I've got a member variable CWidgetDlg MainDlg::m_Widget and a button on CMainDlg with a handler like

CMainDlg::OnDisplayWidgetBtn()
{
 m_Widget.ShowWindow(TRUE);
}

But of course m_Widget hasn't got a HWND setup, and I am trying to remember the right way to do this? For dialog controls I can use DDX but what about child dialogs?

And is this a reasonable approach, or is there a nicer, more automated way?