When drag scroll, page content show incorrectly

[Corey Fu <coreyfu gmail com>]

I use gtk+-2.16.6 and compiled with configure:

--with-gdktarget=directfb \

--without-libtiff \

--with-libjasper \

--with-included-loaders=jpeg,png,jasper \

--disable-glibtest \

--disable-modules


I run the gtk-demo and choose "Source" option, then click the page down
button to scroll the window, the most part of text content is turned to a
black block one, as the attachment show!  I  find that in the process of
scrolling, function _gdk_directfb_window_scroll is called. While my another
application called _gdk_directfb_window_move_region, it has the
same issue: the most part of content is turned to a black block. Is this a
GTK bug or DFB bug? How can I fix it?


Thanks!