UpdateWindow() doesn't work...

[Sam]

Hello !

I would like to have a dialog box that pops up when I click a button.
This works OK : I create a thread using a class derivated from
CWinThread, and the thread creates a dlgObject derivated from the
CDialog class.

I would like the contents of the dialog box to be updated frequently. So
inside the dlgObject::OnPaint(), there is :

pWnd=GetDlgItem(ID_something);

where pWnd is a CWnd* object declared as a global variable.

Then, in the main window, I have a OnIdle(). Inside it, I do :

pWnd->Invalidate();
pWnd->UpdateWindow();

but this doesn't seems to work : it is as if the window doesn't answer :
there's a gray rectangle in it, without anything....

What's wrong with my code ?? What's the best way to implement a
frequently refreshed dialog box ??

Thanks in advance !

Sam