I am using the CDisplay and CSurface wrapper classes that come with DirectX. I am working in windowed mode and am trying to apply a clipper to the m_BackBuffer surface in order to updated specific rectangles on the surface before blt''ing to the m_FrontBuffer. I am using the following code but when I do it doesn''t allow me to write anything to the surface. Can anyone see what I am doing wrong? //create direct draw clipper LPDIRECTDRAWCLIPPER pddclip; m_pDisplay->GetDirectDraw()->CreateClipper(0,&pddclip,NULL); //create the clip region HRGN hrgn = CreateRectRgn(0, 0, 800, 640); DWORD dwBufSize = GetRegionData(hrgn,0,NULL); LPRGNDATA lprd = (LPRGNDATA)malloc(dwBufSize); GetRegionData(hrgn,dwBufSize,lprd); pddclip->SetClipList(lprd,0); //attach the clipper to the BackBuffer before blt''ing to it m_pDisplay->GetBackBuffer()->SetClipper(pddclip); Thanks for the help! Todd