Many applications help users learn how to use new features, but few actually help users understand what's happened when things go wrong, nor how to fix it.
Crystal is application framework (written in Java and using the Swing toolkit) that extends the work of the Whyline, enabling the creation of software applications that allow users to ask questions about their data and the application's state.
For demonstration, we've implemented a word processor with Crystal that allows users to asky "Why 'teh' change to 'the'?" and "Why is this whitespace here?" You can see a demo of it in the video.