If this ever becomes part of the XUL core we'd need to make sure it works with our accessibility API support (MSAA and ATK). Most likely that would require some work. We expose the "disabled" state on each widget.

(From Alex: I don't foresee it becoming part of the XUL core by any means. I might wish otherwise, but I don't see it happening. The script I wrote is a hack, and probably doesn't affect anonymous controls.)