In QuarkXPress, characters which don't printtabs, spaces, ends of paragraphs, and so onare called
invisibles . InDesign calls these
hidden characters , and you make them visible (or invisible again) by selecting Show Hidden Characters from the Type menu or pressing Command-Option-I/Ctrl-Alt-I. (In XPress, the shortcut is simply Command-I/Ctrl-I.) The characters appear in the color of the current layer.