Gtk+-2.17.2 + directfb Scroll black area bug fixed

Modify gdkgeometry-directfb.c will fixed

/*if (gdk_rectangle_intersect (&rect, &clip_rect, &rect) &&
(!private->update_area ||
!gdk_region_rect_in (private->update_area, &rect)))
{
GdkRegion *region;

region = gdk_region_rectangle (&rect);
gdk_region_subtract (invalidate_region, region);
gdk_region_destroy (region);

if (impl->surface)
{
DFBRegion update = { rect.x, rect.y,
rect.x + rect.width - 1,
rect.y + rect.height - 1 };

impl->surface->SetClip (impl->surface, &update);
impl->surface->Blit (impl->surface, impl->surface, NULL, dx, dy);
impl->surface->SetClip (impl->surface, NULL);
impl->surface->Flip(impl->surface,&update,0);
}
}*/