SYSTEM.FORM_STATUS represents the status of the current form.
The value can be one of three character strings:
CHANGED Indicates that the form contains at least one block with a Changed record. The value of SYSTEM.FORM_STATUS becomes CHANGED only after at least one record in the form has been changed and the associated navigation unit has also changed.
NEW Indicates that the form contains only New records.
QUERY Indicates that a query is open. The form contains at least one block with QUERY records and no blocks with CHANGED records.