Small but annoying problem

I was wondering where the choices that show up when you right click on a file and go to "Open With" come from. I've got KWrite showing up twice as well as another application. I'd really like to have them there only once. I've cleaned up File Associations so that each app is only there once and checked root's file associations to be sure that the extra entry isn't coming from there. Any other file I should know about to edit? Thanks in advance for your help.