For the Index, the navigation-control table shows an array of letters, possibly preceded by items Sym and Num. The array shows only those letters for which actual index entries exist. When the Index tab is first displayed, the first item in the array shows as selected; however, any subsequent user selection is stored, using persistent cookies. The navigation pane displays the index entries for the selected letter, in an expanding form if in the .ohx file idxExpand is set. While the number of levels is not limited by OmniHelp, there is a practical display limit of about nine levels, and after six very little of the text is shown. However, since hovering over any bit of an entry displays a tooltip with the full entry title, this is not a major problem. A horizontal scrollbar is also provided.
As with the Contents, the Index presents all destinations as direct links, in each case showing the full title of the topic referenced. There are no additional dialogs to navigate when an index entry links to multiple topics, and a user can tell instantly if the link is to a topic already viewed. We consider this an improvement over older designs.