zDE now provides caching of UDM trees on a per-session basis.

• Suppose you have logged into your site and another user is also using the same zDE and site, then the zDE treats them as two different sessions. You can thus simultaneously edit multiple UDMs and zDE will save the changes.
  
• During Editing, this reduces the loading time for complex UDMs.

• The future versions will offer Version Control and a mechanism to check out UDMs so only one designer at a time can make changes but all the other users who have the existing version can work on it in Read Only mode. 
  
  This Caching Mechanism is, however, not available for multiple sites.