Child Window painting problem on Vista only

Question

I have a dialog-based MFC C++ app. My dialog displays a number of "pages" (similar to a tab page or property dialog box).

I display each "page" by displaying a Child window over the top of the parent's client area. This works fine on Vista until I then open another window on top of the child.

Vista then seems to draw a thick white rectangular frame within my parent dialog box which paints over the top of my "page" child window(s). If I move another window over the top of this white rectangle, it will repaint the obscured area just fine.

Can somebody please tell me what is going on? Is Vista trying to clear my non-client (frame) area using incorrect coordinates perhaps?

My parent dialog is a skinned class derived from CDialog which handles the painting of my own window titlebar and frames. I've found that if I don't call CDialog::OnNcActivate() within my own OnNcActivate() method, the white rectangle doesn't appear. Of course if I do this then I can't use my child windows.. but OnNcActivate would appear to be related to the problem.

Answer 1

I've figured out the problem.. I shouldn't be calling CDialog::OnNcActivate() - I should have just been returning TRUE instead. All working fine now.