Thank you. I had this problem, too.
According to that forum post, just put the following code in
~/.mozilla/firefox/<profile_name>/chrome/userChrome.css
Code:
@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
menu.bookmark-item > .menu-iconic-left {
visibility: visible;
}
If there isn't a chrome folder and/or userChrome.css, just create them.
For the newbs (I am one): to see the mozilla folder in your home profile, you have to use shortcut CTRL+H to see hidden folders.