Thanks again for your advice. I will try this. BTW, when calling InvalRect, the area which specified rectangle argments will clear with background color in my environment, and this causes flicker. If the area was small, we cannot notice that but when updating whole window, we will notice it. So I call directly redraw routine. How can I add a rectangle or region without clearing such area with background color? TIA. Osamu Shigematsu >Try using: > > CALL INVALRECT(gObjSelT) > >to force PGPro to update the user object.