@Override
	public FieldLocation getFieldLocation(ListingField lf, BigInteger index, int fieldNum,
			ProgramLocation programLoc) {
		if (!(programLoc instanceof OperandFieldLocation)) {
			return null;
		}
		OperandFieldLocation loc = (OperandFieldLocation) programLoc;

		if (!hasSamePath(lf, loc)) {
			return null;
		}
		return getFieldLocation(index, fieldNum, lf, loc.getOperandIndex(), loc.getCharOffset());
	}
@see ghidra.app.util.viewer.field.FieldFactory#getFieldLocation(ghidra.app.util.viewer.field.ListingField, BigInteger, int, ghidra.program.util.ProgramLocation)
Ghidra/Features/Base/src/main/java/ghidra/app/util/viewer/field/OperandFieldFactory.java