It would be really useful for me to be able to filter rows based on a field value. E.g. filter out all rows that are NOT NULL in a table.
EDIT: For clarity, I mean it would be useful for me to not display rows that have a null value for a certain field in the table view. This would filter out unnecessary records and clean up the record list for my user's.
Not sure if this is possible, but just a suggestion.
This functionality was introduced in dbFront 1.0.9.0973
Beside each Advanced Filter field you will see a checkbox with a tool tip indicating that you can filter on empty values. As of 1.0.11, Empty values include both Null and Blank values.