Widget expands and collapses several times

I haven't seen this myself, but users of the site have been reporting something similar. I've used the same browsers as them and can't replicate it.

I'm having this problem as well. It is difficult to track the cause because it works fine at first. It seems like if I leave the page open in my browser for a long time, eventually it'll happen, but I don't have the patience to find a reproducible cause. At first it'll be fine, then it might open and close a couple of times, and eventually it'll be opening and closing a dozen times.

In my case, after uploading an image to a field, no matter if it's before or after the tree, the expand/collapse buttons behave as if clicked twice.
Removing the image or adding a new one makes it behave as if clicked 3 times, and so on.
This happens using either throbber or progress bar for the image upload.
My knowledge is limited but something similar happened to me here and I solved it in a dirty way (creating a page variable and checking for it's existence to stop attaching the click function).
If someone can confirm this finding, I'll try to look into the code to create a patch, I guess if my assumption is correct, it should be an easy fix to those who know a bit more than me.

The problem is the .attach() function is called again when there is an Ajax event - this attaches the jquery click() handler to the expand/collapse buttons AGAIN. So after that, the expand/collapse click handler is called twice.
I am pretty sure this is also the cause for this Taxonomy Manager issue :
Incompatibility with Term Reference Tree Module

Here Managing JavaScript in Drupal 7 I read that you should use jquery once to circumvent this problem.
I have made a simple fix by adding once() as a filter before the click():

term_reference_tree.js line 5:
$('.term-reference-tree-button', context).once().click(function() { // once() used to avoid the click handler being attached multiple times (otherwise attach is called for each AJAX refresh)

This is whats in the patch.

This was resolved using #1509356: strange module behaviors when uploading image

anche a me lo stesso problema, dipendeva da hierarchical select, disinstallato e ora tutto ok