I want to delete GTK themes which come by default in ubuntu 10.10. As I open appearance, theme delete button is shown disabled for me. How I can delete theme by using Appearance instead of going to command line?
I've got an easy way to do this. Ubuntu Guide very clearly demonstrates the steps needed to delete themes from appearance menu
These themes are installed during Ubuntu installation and available system-wide. You need root to remove them. However, removing them might cause unexpected behavior.
But if you insist, you can check which package owns the theme (for example, New Wave) and remove it:
$ cd /usr/share/themes $ dpkg -S `pwd`/New\ Wave $ aptitude remove gnome-themes-ubuntu # not recommended