Assume Mint 7 main edition (Gnome desktop..)Once selected, you will have to logout/login again or try restarting the desktop ctrl alt backspace keyboard combination
--also it is possible not all icons will have text entries
The other way of working on the desktop is via gconf-editor
which offers more control, but is easier to cause mistakes when used..
http://en.wikipedia.org/wiki/Gconf-editor