Conflict with collapse.js

I appear to be having some sort of conflict between TinyMCE and collapse.js, which causes pages to fail to load. For a minute, it appears that the page loads (the title bar displays the correct page title), but then it stops, the title bar reverts back to a blank title, and the screen displays a "disable rich text editor" link on a totally white screen. Then the browser continues to spin, but without finishing and loading the rest of the page.

Oddly, this does not happen on node/add pages, but it does happen on node/123/edit pages, and also on user/123/edit pages.

By process of elimination, I managed to figure out that the problem was in collapse.js, and by poking around in there, I was able to fix the problem by changing the following block of code (collapse.js, l 66 - 74):

      $(this).empty().append($('<a href="#">'+ text +'</a>').click(function() {
        var fieldset = $(this).parents('fieldset:first')[0];
        // Don't animate multiple times
        if (!fieldset.animating) {
          fieldset.animating = true;
          Drupal.toggleFieldset(fieldset);
        }
        return false;
      })).after($('<div class="fieldset-wrapper"></div>').append(fieldset.children(':not(legend)')));

to:

      $(this).empty().append($('<a href="#">'+ text +'</a>').click(function() {
        var fieldset = $(this).parents('fieldset:first')[0];
        // Don't animate multiple times
        if (!fieldset.animating) {
          fieldset.animating = true;
          Drupal.toggleFieldset(fieldset);
        }
        return false;
      })); // .after($('<div class="fieldset-wrapper"></div>').append(fieldset.children(':not(legend)')));

As far as I can tell, all I'm doing is degrading the appearance of the animation a bit, not actually screwing up the functionality. Still, all things being equal, I'd like to avoid hacking up core, and more than that, I suppose there's a chance I'm screwing up some functionality somewhere.

I've installed TinyMCE in dozens of other sites, and have never had this happen to me. I'm using a custom theme, but I got the same behavior when I reverted to Garland, so I don't think that's it.

Has anyone else experienced something like this, or have I fallen off the long tail of tinymce installs?

Details:

Drupal version: 5.7
TinyMCE module version: 5.x-1.9
TinyMCE core version: 2.1.3

Any help would be greatly appreciated!