Classic problem. It seems we are starting into Ext and are trying to identify the best ways to work with it without trial-and-error.
How does your project design/mockup screens for Ext? What tools and workflow do you use? Or does your team just consist of hard-core coders and they create interfaces that are tweaked after user comments?
It depends. Before I started out with ExtJS 2, I had some HTML templates which I could quickly put together and create ExtJS 1.x forms with that.
Now, with ExtJS 2, I use Visual Studio to create dialogs. I also tried out several of those ExtJS Gui Builders, but at date, none of them works correctly, or they don't work at all. So I end up building GUI mockups with the free Visual Studio applications. After my customer accepts the mockups and when the application has been built, there are often changes to the original mockups which I either implement directly (because it's clear which changes are required) or I do a screenshot and edit it in Photoshop.
I wish that sometimes we get a full-fledged GUI builder tool which works two-way (just like Trolltech's QT Desginer or VS).