Gtktextview scroll bar issue (emergency)

["Wang, Pengzhuo" <Pengzhuo Wang windriver com>]

Hi all,
    I am porting gtk+directfb to arm926 platform. 
After porting, run gtk-demo, and found some issue about control
gtktextview.

When dragging scrollbar up/down. visible part of gtktextview turn
black(background color), so
I can not see the content of textline.

What cause this issues? Gtktextview or gtktextlayout or gtktextdisplay
's issue? Or pango's issue? 

Anyone can help me? Thanks in advance.
 
The following is my package versions:

DirectFB --->1.3
Gtk+ --->2.16.0
Glib -->2.18.4
Pango --> 1.22.4
Cairo ---> 1.8.6
Atk ---->1.24.0


Best Regards
 
pengzhuo wang(bobwang)
Professional Service | WindRiver P.R.China
Room3-H,New JinQiao Plaza, 
No.585 Xizhang Rd(M),Shanghai,200003,P.R.C
Tel:86-21-63585586/87/89/90 ext.208 Fax:86-21-63585591