Exception if remove event listener from detached element, then add to document

What steps will reproduce the problem?
foo=createElement(svgns, 'rect');
foo.addEventListener('mouseover', f, false);
foo.removeEventListener('mouseover',f,false);
svgRoot.appendChild(foo)

What is the expected output? What do you see instead?
This throws an exception: 'addMe' is null or not an object

The problem is that after the event listener is deleted, the list entry is 
replaced with undefined, but the code later that adds the event listeners does 
not check to make sure the listener is still there.

Original issue reported on code.google.com by grick23@gmail.com on 30 Jun 2010 at 2:58

lewisje / svgweb

Exception if remove event listener from detached element, then add to document #528