Can't access find/change history

Hi guys, hoping someone may have encountered this and know what I'm doing wrong. I can't find it in the manual or in Kvern's book (Real World ID2).

Every once in awhile when I'm using the find/replace function in ID2, I am suddenly able to use the down arrows just to the right of the field boxes to access the history of previously used searches. This is extremely useful to me, as there are quite a few searches we do all the time to get rid of various formatting problems, etc., from the native files our writers provide.

Most of the time, however, these arrows are greyed out and I can't access those very useful stored searches. This is in the same document and/or a document from the same template, so I have no idea why it suddenly becomes accessible every now and again. I can only guess that I've accidently hit a series of keystrokes that unlocks it.

If anyone can sort me out on this, I'd be extremely grateful. I tried to search for a previous discussion on the subject but couldn't find anything.

TIA,

Cheryl