In the default editing mode for the compose window, there are two keys that will move the cursor to the end of the line: [End] and Ctrl-E . Open a new compose window and clear it completely. Type some characters, e.g. "abc". Press [Home]. The window looks like "|abc". Press [End] and it shows "abc|". Press [Home] again and type Ctrl-E. The cursor does not advance to the end of the line. When there are line(s) following, the behaviour of [End] and Ctrl-E is identical.