Although invisible headers are normally used within a program as a way of identifying individual memos for internal use (such as file reconstruction), you can create and edit them as an operator. To do this, move the cursor to the first position in the memo and hit the ^S^H keys. The terminal will beep, and if there is an existing header, it will display in dim, overwriting the existing display. To exit without changing the header, hit Escape. To remove the header, hit Enter. Otherwise type in a new header and hit any control key to exit from header mode. When you exit from header mode, the original first line of the memo will be redisplayed.