[kh99]

I think the problem is that the javascript code that builds the color and font menus (in clientscript/vbulletin_textedit.js) uses for...in loops to add the items, and that kind of loop gets all properties of an object, including anything added to the prototype. (As explained here: http://www.prototypejs.org/api/array).

So maybe the easiest thing to do is to change that JS code that you've added. It wouldn't be that hard to move the "contains" and "remove" code in to the code below where they're called (assuming of course that there isn't any more JS code on that page that relies on those functions).