Letter disappear in X-windows, why?

[Jon Ingason]

Following is output from terminal windows in Gnome terminal:

[jonsi at lea ISO]$ more /boot/grub/device.map
# this device map was generated by anaconda
(hd0)     /dev/sda
[jonsi at lea ISO]$ ls
Bilder
Bodhilinux
Fedora-14-i386-DVD
Fedora-14-x86_64-DVD
Fedora-15-i386-DVD
Fedora-15-i686-Live-LXDE
Fedora-15-x86_64-DVD
finnix-102.iso
g4l-v0.34.iso
geexbox-1.2.4-en.i386.glibc.iso
geexbox-1.2.4-en.x86_64.glibc.iso
KNOPPIX_V6.0.1CD-2009-02-08-EN.iso
smoothwall-express-3.0-sp2-i386.iso
systemrescuecd-x86-1.5.8.iso
Toorox_09.2010-32bit_GNOME.iso
ubcd411.iso
Ubuntu
USBBOOT
WindowsDeveloperPreview-64bit-English-Developer.iso
VirtualMachines

Link to png file which is dump from same windows:

http://www.ingason.se/blogg/wp-content/uploads/2011/09/Sk%C3%A4rmbild-Terminal.png

The problem is that som letters disappears like the r in "more" and 
"grub" in the first line and "generated" in the second line and the h in 
"this" in the second line and in "hd0" in the third line etc. Same 
letters are also missing in menu label. I have seen this for a while and 
if I log out then usual the letters comes back. Next time it is other 
letters the disappear. Other user logged in at same time can have 
different letters disappearing.

If i copy this text to my from the terminal windows in to my mail client 
I get all letter just as shown above.

I am running F14 patched up to date.

uname -a
Linux lea 2.6.35.14-96.fc14.x86_64 #1 SMP Thu Sep 1 11:59:56 UTC 2011 
x86_64 x86_64 x86_64 GNU/Linux

lspci
01:05.0 VGA compatible controller: ATI Technologies Inc RS690 [Radeon 
X1200 Series]

The DE is Gnome 2.

My question is, is someone having same problem? How can I solve this?
-- 
Regards
Jon Ingason