question: protected void updateAnnotations ( Annotation existingAnnotation , Position newPos , Map additions , List modifications , List deletions ) { if ( existingAnnotation instanceof FoldingAnnotation ) { FoldingAnnotation foldingAnnotation = ( FoldingAnnotation ) existingAnnotation ; if ( newPos != null && newPos . length > 0 && projectionAnnotationModel != null ) { Position oldPos = projectionAnnotationModel . getPosition ( foldingAnnotation ) ; if ( ! newPos . equals ( oldPos ) ) { oldPos . setOffset ( newPos . offset ) ; oldPos . setLength ( newPos . length ) ; modifications . add ( foldingAnnotation ) ; } } else { deletions . add ( foldingAnnotation ) ; } } }
target:  This is the default behavior for updating a dirtied IndexedRegion. This function can be overridden if slightly different functionality is required in a specific instance of this class.