About licensing issues related to GWT Libraries

A couple of weeks ago, I've been looking for GWT Libraries in order to develop GWT Applications quickly. I found some GWT Libraries such as GWT Ext, GWT incubator, and Ext GWT (Also knowing as GXT). With respect to GWT Ext, this library has a lot of widgets that we need to develop the Application. However, people have written on several posts that it's inefficient due to third party Java Script library it uses.

About GXT, I though I couldn't use this library because it has dual licensing. I had to write an e-mail to GXT Team in order to know if I could use GXT with System that has GPLv2 License. Fortunately, the answer was the following.

Juan,

If you add "or any later version" to the GPL v2, you will remove any technical issue you might have. We don't have an issue with GPLv2. We don't see a conflict.

The Ext Team

I'm really happy with this answer because currently, GXT is one of the best library that I found.