When an SDL-OpenGL window is dragged, what event to handle to update client area?

Because when I drag the window and some part of it goes outside the screen and back, it won't repaint (swap the buffers) until I release it. WM_PAINT isn't generated. Should I swap the buffers on WM_NCPAINT instead? I think I'm going to swap the buffers on WM_MOVING... Thanks. EDIT: Nope, swapping during WM_MOVING won't do the trick. [Edited by - owl on February 1, 2009 11:01:21 AM]