Connexions/atc — pull request #5 by philschatz (2013-04-16 17:53:15+00:00)
Title: Atc tree and save cleanup

The DnD Tree UI had some quirks:

- Took a long time to expand/collapse a node if the book was large
- Had bugs when dropping various Types of content on each other
- Bugs creating a new piece of Content, Book, or Folder

Also, the dirty bit on models was not being set properly so the save button did not get enabled properly and did not save all the changed models.