@Override
		public FieldElement substring(int start, int end) {
			AttributedString as = attributedString.substring(start, end);
			if (as == attributedString) {
				return this;
			}
			return new OperandFieldElement(as, row, operandSubIndex, column + start);
		}
@see docking.widgets.fieldpanel.field.FieldElement#substring(int, int)
Ghidra/Features/Base/src/main/java/ghidra/app/util/viewer/field/OperandFieldHelper.java