Help removing slight switch flicker

I have this windowed DirectX program with a tab-control being a child to the "main" window. Each "page" has a child window where the rendering takes place (using swap chains). When the tab changes I hide the currently visible child window then show the newly selected child window.

Now, generally everything works fairly ok except when selecting a new tab there is sometimes a slight flicker appearing the instant it changes.

I guess this is caused by some of the controls being rendered (tabview or child window, the main window has no background brush), but validating their areas (ValidateRect) after showing/hiding still causes flickers. Any ideas what might cause it and how to prevent it?

Well if it's MFC I had the same problem with one renderer. I'm not drawing to the DC of the window because the renderer is using it's own window inside of a window.

My solution was to trap EvEraseBkgnd and always return TRUE. The double buffer for DirectX took care of the rest and the flicker is gone.

Dunno if it will help for you. I believe the message to trap for is WM_ERASEBKGND. Not sure but you can look it up in the Platform SDK.

EDIT: Now that I've seen some of your previous posts I'm also thinking you are using threads. You will get flicker when one thread attempts to access a resource that another thread is already using. You can prevent this by using WaitForSingleObject() and the other thread functions available in the API. I had the same problem when my renderer would render tiles at the same time the tile picker window would render the same tiles. As they both rendered the same tiles, the set in the tile picker window would flicker. Annoying as heck.