1. Launch the WINS debugger.
3. Launch an application with which the flicker can be reproduced.
4. Type ctrl-alt-shift-f to enable Window Server auto-flushing. [This will allow you to see the effect of each draw command]
5. Put a break point in the draw method that is suspected to be causing the problem (or if you're really in the dark then in CCoeControl::HandleRedrawEvent).
6. Type ctrl-alt-shift-r - this will cause a full screen redraw and the debugger should stop at your break point.
7. Step through the draw code, observing the effect of each draw command on the emulator window.
For more Tips Refer : Debugging Draw Function