admin_menu.js + firebug = slow

I'm using
drupal 6.14
admin_menu 6.x-1.5
Firefox 3.5.5
Firebug 1.4.5

For a reason unknown to me, Firebug is slowing all my javascript down a lot, to the point where I get unresponsive script warning (up to 30 seconds, if I increase the limit). (I'm getting the warning in German, so I don't know how it would read in English).

Usually the position of the script complained about is inside Firebug's own scripts, but often it is in jquery.js. I think it is usual jquery stuff blown up with firebug overhead.

I did a bit of debugging, and I found that things get better if I disable admin_menu.
I did more debugging, and found that a lot of time is spent in admin_menu.js:

  // Delayed mouseout.
  $('#admin-menu li').hover(function() {
    ...

The code triggers an each() loop inside jQuery, that binds a mouseenter event to each list element.

I found that this code can be speed up by

  // Delayed mouseout.
  $('#admin-menu li.expandable').hover(function() {
    ...

which reduces the number of matches.

I know, there is really no reason why this simple iteration should take so long, even with a big admin_menu. I explicitly blame firebug, or something in my own website that is screwed up.

However, if there is such a simple and obvious way to speed things up, then I say, why not?
The patch is made for 6.x-1.5.