Can't see text in box

Not sure of the proper terminology.

The box next to the search box doesn't show any text.

On many web sites where it normally shows "ok" or "submit" and so on i'm unable to read it and sometimes I can't even see the box.

Sometimes I have to maneuver the cursor just to see it change to the hand so I now know this is where to click.

In this screenshot on top right you can't see any text in the right box.

http://imageshack.us/photo/my-images/263/snipm.png/

Win 7 home prem
Firefox
No infections