code: public SpanManager delete(int start, int end){
  		sb.delete(start, end);
  		adjustLists( start, start-end );
  		
  		if(calculateSrcPositions) for( int i = 0; i<end-start; i++) ib.remove( start );
  		
  		return this;
  	}
docs: Deletes the content between start (included) and end (excluded).