// flush all pending repaints before we change m_{x,y}ScrollPosition, as
// otherwise invalidated area could be updated incorrectly later when
// ScrollWindow() makes sure they're repainted before scrolling them
// flush all pending repaints before we change m_{x,y}ScrollPosition, as
// otherwise invalidated area could be updated incorrectly later when
// ScrollWindow() makes sure they're repainted before scrolling them