Steps to reproduce:

1. Create a tree as shown in the screenshot below:
   
2. Add ibexa_taxonomy_assignment to a "Folder" Content Type and a create new Folder.
3. Add 5 and 9 tags - do not save content, just continue to the next step.
4. Open tree again and click on 5 tag - checkbox should be unset, confirm.
5. Changes didn't update.
6. Click on "Select tags" again.
7. Click on "Select tags" again and select different tags from a tree.

Result:
Rendered chosen tags don't reflect one's choices in the Tags tree selection.

Expected result:
Rendered chosen tags should reflect one's choices made in the Tags tree selection.