question: final Region cutChildren ( Region r , final LWComponentPeer < ? , ? > above ) { boolean aboveFound = above == null ; for ( final LWComponentPeer < ? , ? > child : getChildren ( ) ) { if ( ! aboveFound && child == above ) { aboveFound = true ; continue ; } if ( aboveFound ) { if ( child . isVisible ( ) ) { final Rectangle cb = child . getBounds ( ) ; final Region cr = child . getRegion ( ) ; final Region tr = cr . getTranslatedRegion ( cb . x , cb . y ) ; r = r . getDifference ( tr . getIntersection ( getContentSize ( ) ) ) ; } } } return r ; }
target:  Removes bounds of children above specific child from the region. If above is null removes all bounds of children.