Forms 3.0/ list_values (LOV)

A have a small problem: I use very often the LOV (List Of values) Pop-up window to let the user select an item. Pressing [Next Field] moves the cursor to the "Find:" field. Normally one can type in text to narrow the list.
In one case, the field *does not display* the characters typed! I compared with other LOVs, but I couldn't find out what could be the difference.

Any ideas why this happens? Btw, narrowing the list works, but the cursor stays at the first position, and nothing is displayed.

Thanks for any help.

   Martin Berli

Internet: berli_at_switch.ch  | SWITCH, Swiss Academic and Research Network
Phone   : +41 1 268 1540   | Limmatquai 138
Fax     : +41 1 268 1568   | CH-8001 Zurich