Editing a polygon coverage layer without loading it totally into OpenJUMP

The feature to be edited is selected with SQL query
SELECT * from table WHERE parcel_id=12345

A new SQL query with a BBOX filter is done for getting the neighbouring parcels into the project and for presenting the situation in the DB before editing. 

BBOX query is repeated and the second polygon layer is made editable.  Adjacent parcels are edited together for preventing overlapping polygons and gaps.

Once editing is ready the changed features are selected with a spatial query.

Spatial query selects the features which must be updated.  Same system works also in new features are added, but not with deleted features.