How to select sub-terms in taxonomy when creating content? In creating a document management system I've created a taxonomy vocabulary with this structure:

Accounting
  Client 1
  Client 2
Client 1
  Contacts
Client 2
  Contacts
  Correspondance
Leasing
  Client 1
  Client 2


Then, in my Document content type I've created a term reference field called Tags which uses autocomplete. The autocomplete part works great, but I don't know how to differentiate Accounting:Client 1 from Leasing:Client 1 from Client 1 (parent level). When loading a new document, is there a way to reference these terms properly?
Simple Hierarchical Select is the module for the job.


  Simple hierarchical select defines a new form widget for taxonomy fields to select a term by "browsing" through the vocabularies hierarchy.


Just change the widget-type of field Tags to "Simple hierarchical select" after you install the module. This guide might come handy if you're running 7.