I used Protection to create a form where user could move with tab only in
those cells which must be filled in. This worked nicely until I tried to
search (ctrl+f).

When I use "Find next", nothings happens. It doesn't help even though the
cells are unlocked; Find doesn't go there. Only when I choose to unlocked
cells, it works. "Find all" lists all hits, but is inconvenient.

Have you noticed this before? Is there any hints how to fix it?