Filter by form does not work

Beta 128 on WinXP

Filter by Form was working beautifully and then I must have done something
that set something that stopped it from working. Now when I click on the
Filter by Form button I can enter a criteria, but there is nothing I can do
with it and the form navigation bar had disappeared.

I thought it might have something to do with the installation, but this
afternoon I installed build 128 and it does the same.

It is not the underlying database (MySQL), because when I create a database
using the OOo native database it does the same.

Any suggestions how to "reactivate" Filter by Form?

TIA
Gert