Python Development Environment with all batteries included
Eric is a Python IDE written using PyQt and QScintilla. It provides various features such as any number of open editors, an integrated (remote) debugger, project management facilities, unittest, refactoring and much more.
The XUL (XML UI Language) project provides free test suites to help ensure interoperability between different XUL motors/browsers and free, open-source show-case examples (aka blue prints) to demo the power of XML for creating UIs.