Combining best of both worlds : One of the most popular opensource CRM (Customer Relationship Management) software is now using extjs javscript library a lot for user interface quickies.

Developers will love documentation around various implementation of this AJAX library : Since Sugar 5.1, the search is layout out via type-ahead combo box system called QuickSearch based around ExtJS. In version 5.2, a lot of tools  feature powerful interaction javascripts, such as the email reader / composer (imazge above), or the application studio, located in  The Developer tools sub-panel that displays options to build new modules and customize existing ones. The Module Builder enables you to build custom modules and Studio enables you to customize existing modules. Creating  relationships between modules is also an option while removing default modules is as easy as performing drag and drop operations within the admin.