In the alphabetical index entries editor window, the entriues are shown one at a
time. The user is supposed to click < and > buttons to go to the previous and
next match.

This is not convenient at all, because the user cannot reach the desired entry
quickly. He has to cycle through all the entries till he comes across the
desired entry.

Provide one or more of the following mechanisms for a quicker access: 
1. Provide a pulldown menu of entries already entered in the document, so that
the user can select from them.
2. Provide a type-ahead (predictive) text entry. For example, if I click in the
field and type "re", and then press DownArrow, all entries beginning with "re"
should be listed (just like the addressbar of a browser.)