I have noticed a similar problem .

-Computer-
Processor		: 2x Intel(R) Core(TM)2 Duo CPU     P9400  @ 2.40GHz
Memory		: 3566MB (833MB used)
Operating System		: Ubuntu 9.04

Date/Time		: Mon 11 May 2009 18:35:25 NZST
-Display-
Resolution		: 1280x1024 pixels
OpenGL Renderer		: Mesa DRI Mobile Intel® GM45 Express Chipset GEM 20090114 x86/MMX/SSE2
X11 Vendor		: The X.Org Foundation
-Multimedia-
Audio Adapter		: HDA-Intel - HDA Intel
-Input Devices-
 

Operating System
----------------

-Version-
Kernel		: Linux 2.6.28-11-generic (i686)
Compiled		: #42-Ubuntu SMP Fri Apr 17 01:57:59 UTC 2009
C Library		: GNU C Library version 2.9 (stable)
Default C Compiler		: GNU C Compiler version 4.3.3 (Ubuntu 4.3.3-5ubuntu4) 
Distribution		: Ubuntu 9.04
-Current Session-

Desktop Environment		: GNOME 2.26.1
-Misc-
Uptime		: 1 hour, 20 minutes
Load Average		: 0.02, 0.24, 0.31

Kernel Modules
--------------

-Loaded Modules-
isofs
udf		: Universal Disk Format Filesystem
crc_itu_t		: CRC ITU-T V.41 calculations
i915		: Intel Graphics
drm		: DRM shared core routines
binfmt_misc
ppdev
bridge
stp
bnep		: Bluetooth BNEP ver 1.3
input_polldev		: Generic implementation of a polled input device
joydev		: Joystick device interfaces
lp
parport
snd_hda_intel		: Intel HDA driver
snd_pcm_oss		: PCM OSS emulation for ALSA.
snd_mixer_oss		: Mixer OSS emulation for ALSA.
arc4		: ARC4 Cipher Algorithm
snd_pcm		: Midlevel PCM code for ALSA.
ecb		: ECB block cipher algorithm
snd_seq_dummy		: ALSA sequencer MIDI-through client
snd_seq_oss		: OSS-compatible sequencer module
snd_seq_midi		: Advanced Linux Sound Architecture sequencer MIDI synth.
snd_rawmidi		: Midlevel RawMidi code for ALSA.
snd_seq_midi_event		: MIDI byte <-> sequencer event coder
snd_seq		: Advanced Linux Sound Architecture sequencer.
iwlagn		: Intel(R) Wireless WiFi Link AGN driver for Linux
iwlcore		: iwl core
snd_timer		: ALSA timer interface
snd_seq_device		: ALSA sequencer device management
led_class		: LED Class Interface
snd		: Advanced Linux Sound Architecture driver for soundcards.
btusb		: Generic Bluetooth USB driver ver 0.3
mac80211		: IEEE 802.11 subsystem
hid_logitech
sdhci_pci		: Secure Digital Host Controller Interface PCI driver
soundcore		: Core sound module
psmouse		: PS/2 mouse driver
uvcvideo		: USB Video Class driver
ff_memless		: Force feedback support for memoryless devices
dcdbas		: Dell Systems Management Base Driver (version 5.6.0-3.2)
sdhci		: Secure Digital Host Controller Interface core driver
snd_page_alloc		: Memory allocator for ALSA system.
serio_raw		: Raw serio driver
intel_agp
pcspkr		: PC Speaker beeper driver
cfg80211		: wireless configuration support
compat_ioctl32
videodev		: Device registrar for Video4Linux drivers v2
iTCO_wdt		: Intel TCO WatchDog Timer Driver
iTCO_vendor_support		: Intel TCO Vendor Specific WatchDog Timer Driver Support
agpgart		: AGP GART driver
v4l1_compat		: v4l(1) compatibility layer for v4l2 drivers.
usbhid		: USB HID core driver
video		: ACPI Video Driver
output		: Display Output Switcher Lowlevel Control Abstraction
ohci1394		: Driver for PCI OHCI IEEE-1394 controllers
ieee1394
e1000e		: Intel(R) PRO/1000 Network Driver
fbcon
tileblit		: Tile Blitting Operation
font		: Console Fonts
bitblit		: Bit Blitting Operation
softcursor		: Generic software cursor







Display
-------

-Display-
Resolution		: 1280x1024 pixels
Vendor		: The X.Org Foundation
Version		: 1.6.0
-Monitors-
Monitor 0		: 1280x1024 pixels
-Extensions-
BIG-REQUESTS
Composite
DAMAGE
DOUBLE-BUFFER
DPMS
DRI2
GLX
Generic Event Extension
MIT-SCREEN-SAVER
MIT-SHM
RANDR
RECORD
RENDER
SECURITY
SGI-GLX
SHAPE
SYNC
X-Resource
XC-MISC
XFIXES
XFree86-DGA
XFree86-VidModeExtension
XINERAMA
XInputExtension
XKEYBOARD
XTEST
XVideo
-OpenGL-
Vendor		: Tungsten Graphics, Inc
Renderer		: Mesa DRI Mobile Intel® GM45 Express Chipset GEM 20090114 x86/MMX/SSE2
Version		: 2.1 Mesa 7.5-rc1
Direct Rendering		: Yes