When you add a word to an index, QuarkXPress tags it with brackets or a box; these are called index markers. Index markers are displayed in a document when the Index palette is open (View > Show Index). You can customize the color of index markers using the Index Preferences dialog box.
Note: When you index a range of text, it is marked with brackets. When you place the Text Insertion bar in text and enter an index entry, the location is marked with a box.