According the documentation As of jQuery 1.7, the queue option can also accept a string, in which case the animation is added to the queue represented by that string.

In jQuery 1.9.1 though my experience is that this feature doesn't work.

This code didn't add the fade-in effect to the queue

$(to_show).fadeIn(
 {
   queue: QUEUE_NAME,
   duration: 'slow',
   complete: function()
   {
     alert('hello');
     $(to_show).after(COLLAPSE_LINK_HTML);
     collapsify_dequeue(container)
    }
 }
);

Full code here http://jsfiddle.net/HYaJ9/

When I removed the queue option the effect did get added to the fx queue. Other effect functions seem to have the same bug, except animate which does successfully handle a string passed to the queue option.

Clarified the docs to indicate you must manually start the queue. http://api.jquery.com/animate/