EDIT: Something stopped this from working recently and I haven't found the solution... YET...
Not listed as a known issue over at Mozilla's site, and hardly mentioned despite extensive Google searches, the solution was pieced together thusly...
- Put %APPDATA%\Mozilla\Firefox\Profiles\ in your Start | Run bar and hit return. Go into the profile folder, then select the chrome folder.
- Note the location in the address bar and open Notepad.
- Enter this in it:
- Save as userchrome.css (making sure to change from .txt to All Files in the drop down to make sure Notepad doesn't autoappend and make it userchrome.css.txt. Make the place saved to the location you noted.
- The Quick Find bar should now have the forward and back and whatnot no longer grayed out.
/* Add Next/Previous Buttons to Quick Find Bar */
.findbar-container>* {display: -moz-box !important;}
Led to it by this:
http://ffextensionguru.wordpress.com/2007/01/10/fx-tweak-quick-find-bar/