Clicking anywhere generates JS warnings in Firefox iff a dropdown menu is present

Created by: qdelettre

I create another issue about this problem, as it is still not solved. See https://github.com/twitter/bootstrap/issues/5566

The JS warning is
Empty string passed to getElementById(). elem = document.getElementById( match[2] );

I use FF 19.0.2 with twitter bootstrap 2.3.0 or 2.3.1 and still clicking anywhere makes a warning in firebug.

Have i missed something ?