In answer this this discussion:
http://www.extjs.com/forum/showthrea...GXT-philosophy
I have created the following project:
http://code.google.com/p/gxt-interfaces/
The goal is to provide a simple way of creating code that is completely testable and mockable via mocking frameworks (such as Mockito) out of the GXT widgets.
Hope this helps. Any ideas, thoughts, suggestions?