Allow only lowest taxonomy terms to assign to nodes I have a lot of taxonomy terms that need to be categorized into multiple categories and subcategories:

- AAA
  - BBB
    - CCC
    - DDD
    - EEE
...


Is there a way how to restrict assigning higher terms to nodes (AAA, BBB) and allow to use only lowest terms (without any child terms - CCC, DDD, EEE)?
Hierarchical Select.  


  Hierarchical Select has the ability to save the entire lineage of a
  selection or only the "deepest" selection. You can configure it to
  force the user to make a selection as deep as possible in the tree, or
  allow the user to select an item anywhere in the tree. Levels can be
  labeled, you can configure limit the number of items that can be
  selected, configure a title for the dropbox, choose a site-wide
  animation delay, and so on. You can even create new items and levels
  through Hierarchical Select!