The on-line help appears at the bottom of the window in yellow type on a navy background --- the two colours understood to be the easiest to read on-screen. Initially, on-line help was designed to be like Macintosh ``bubble-help'' where, as the mouse is moved across areas of the screen, the help messages refer to the particular object (button, box, list, etc.) under the cursor. The first formative evaluation showed that users found this kind of help distracting since it was continually changing. The message content also was less useful than it should have been, focusing on the current object rather than the current task. So a more task-oriented approach was adopted, with messages changing in response to user-generated events.