Firefox parentNode issue

1) Script Title: chromemenu

2) Script URL (on DD):
http://www.dynamicdrive.com/dynamici...rome/index.htm

3) Describe problem:
When you mouse out of a drop down menu into a text input field, Firefox throws a Permission Denied error for parentNode.

I hacked the contains_firefox function to work around as follows:

contains_firefox:function(a, b) {
try {
while (b.parentNode)
if ((b = b.parentNode) == a)
return true;
return false;
}
catch(e) {return false;}
},

I'm aware of FF throwing an error in select situations with regards to the default contains_firefox() code. But it doesn't seem to affect the script's behavior, at least not as far as I can even see.