   TestCooperativeLevel and Alt+Tab
  Hi, I have a problem in using TestCooperativeLevel. The problem happened only when I used Thread to draw on the screen and I change to the other application (GDI) and back to the DirectDraw Application. After tracing, I found that the TestCooperativeLevel always fail and return false.But If I use while statement instead trhead to draw on the screen it work well.  Any Suggestion ... Here''s the code... in C# ----Using Thread------...m_ThreadDraw = new Thread(new ThreadStart(Draw));m_ThreadDraw.Start();...private void Draw(){  while (Created)  {    ProcessNextFrame();// Process and draw the next Frame.Thread.Sleep(50);  }}------ Without Thread(While Statement)-----------...Draw()....private void Draw(){  while (Created)  {    ProcessNextFrame();// Process and draw the next Frame.Application.DoEvent();  }}   Sincerelly,Budi 
  Thank any way, already work out. sorry wrong question...  