Comment 8 for bug 140816

I too have this problem, and adjusting the PNG Plugin in Compiz makes no difference. Reproducible every time. (I do a lot of stretching terminal windows). As Berdir found, it happens occasionally by itself.
HP Pavilion zd8000 laptop 17"
lspci:
00:00.0 Host bridge: Intel Corporation 82915G/P/GV/GL/PL/910GL Memory Controller Hub (rev 0e)
00:01.0 PCI bridge: Intel Corporation 82915G/P/GV/GL/PL/910GL PCI Express Root Port (rev 0e)
00:1c.0 PCI bridge: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 1 (rev 03)
00:1d.0 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #1 (rev 03)
00:1d.1 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #2 (rev 03)
00:1d.2 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #3 (rev 03)
00:1d.3 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #4 (rev 03)
00:1d.7 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB2 EHCI Controller (rev 03)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev d3)
00:1e.2 Multimedia audio controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) AC'97 Audio Controller (rev 03)
00:1e.3 Modem: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) AC'97 Modem Controller (rev 03)
00:1f.0 ISA bridge: Intel Corporation 82801FB/FR (ICH6/ICH6R) LPC Interface Bridge (rev 03)
00:1f.1 IDE interface: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) IDE Controller (rev 03)
00:1f.3 SMBus: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) SMBus Controller (rev 03)
01:00.0 VGA compatible controller: ATI Technologies Inc M24 1P [Radeon Mobility X600]
0b:00.0 CardBus bridge: Texas Instruments PCIxx21/x515 Cardbus Controller
0b:00.2 FireWire (IEEE 1394): Texas Instruments OHCI Compliant IEEE 1394 Host Controller
0b:00.3 Mass storage controller: Texas Instruments PCIxx21 Integrated FlashMedia Controller
0b:00.4 Generic system peripheral [0805]: Texas Instruments PCI6411/6421/6611/6621/7411/7421/7611/7621 Secure Digital Controller
0b:02.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)
0b:03.0 Network controller: Broadcom Corporation BCM4318 [AirForce One 54g] 802.11g Wireless LAN Controller (rev 02)

Again, it's the ATI Mobility on fglrx. Could this be the culprit?