It could be useful if You could set up a value ( You can, but it is not stored ) in the preview ( filter ) field, that was stored for that form, and was used even if the filter-field was not displayed - if it is displayed, then it was used as a default-value, the user could alter or delete.

Even more super it would be, if You could set up if it is for a specific field, ( could be a department name ) or for all fields.

By doing so, You could have a table for a company or club. You could then have a locked page where You had a sign-in for a department. On that locked page You had a Database-viewer-form whwre You had set up a filter "dept1" and a fieldname "department".

You then had "hidden" the selection field.

This should do, that when a user signs in on the locked page, the user only sees the records that matches "dept1" for the field "department". The user is "locked" to "dept1"

Another setup could be that the filter-field was not hidden.

This should do that when a user signs in on the locked page, the user only sees the records that matches "dept1" for the field "department". The user could then edit the fieldvalue to dept2 and then sees all data for dept2 and finally the user could leave the filter-field blank, and then the user would see all data.

Super, super it would be, if there was the possibility of 2 or 3 named filter-fields