I’m using Ubuntu 8.04 Hardy Heron and whenever I change the wallpaper or theme using the Right Click -> Change Desktop background, the CPU usage goes upto 100% in the System Monitor. Even after exiting the ‘Appearance Preferences’ the process ‘gnome-appearance-properties’ persists in the memory consuming the CPU. You’ve to manually kill the process to make the CPU load to normal.
After searching the bug in launchpad, I found that the issue is not fixed yet. But there is a workaround for solving the problem. You’ve to delete the .gtkrc-2.0 configuration file in your home directory. After doing this logout and login. The issue is fixed now. The CPU load becomes normal.
rm -r ~/.gtkrc-2.0
For more information about the Bug [Visit Lauchpad]