There might be situations in which a particular cPanel user mess with his themes and you would want to limit his privilages so that he cant change the theme to a specific one or two. Perhaps you do not want him to change to X Theme or Paper Lantern.
To do this, login to your server as root and create the following file :
/var/cpanel/themes.conf
Edit the file and mention the list of themes which you want to be in the switch theme dropbox in cPanel interface.
For example, if you do not want X theme, the content of the above file would be :
# cat /var/cpanel/themes.conf
x3
paper_lantern
x2
If you want the X theme and do not want paper_lantern, just give x in place of paper_lantern in the file.
That’s it !