The very cool GWT-Ext library was released yesterday by Sanjiv Jivan. It supports the latest Ext 1.1.1 library and the GWT 1.4 final release. There are a bunch of new features including drag and drop support and a host of new Tree widget capabilities including:

• Asynchronous loading of Tree data from Json and XML
• Tree Filtering
• Tree Sorting
• Tree Drag and Drop
• Checkbox nodes and easy styling of nodes

Checkout the showcase example to get an idea of what the library is capable of.