The WordPerfect file format is basically a long stream of bytes representing the text, with special control codes inserted for switching various features on and

The WordPerfect file format is basically a long stream of bytes representing the text, with special control codes inserted for switching various features on and off. In other words (IIRC) reveal codes was made possible largely because the file system representation matched what you saw on screen, so it was easy to keep the visual representation in sync with the file. In Word (certainly now and I think back then as well) it wasn't that way - the file was structured so there was a mis-match between the screen and the file, so keeping the two aspects in sync became more difficult as the in-memory representation was correspondingly structured rather than sequential.