Answering why and why not questions in user interfaces

Modern applications such as Microsoft Word have many automatic features and hidden dependencies that are frequently helpful but can be mysterious to both novice and expert users. The ""Crystal"" application framework provides an architecture and interaction techniques that allow programmers to create applications that let the user ask a wide variety of questions about why things did and did not happen, and how to use the related features of the application without using natural language. A user can point to an object or a blank space and get a popup list of questions about it, or the user can ask about recent actions from a temporal list. Parts of a text editor were implemented to show that these techniques are feasible, and a user test suggests that they are helpful and well-liked.