// we divide it later by GRID_SCROLL_LINE, make sure that we don't
// have rounding errors (this is important, because if we do, we
// might not scroll at all and some cells won't be redrawn)
// we divide it later by GRID_SCROLL_LINE, make sure that we don't
// have rounding errors (this is important, because if we do, we
// might not scroll at all and some cells won't be redrawn)