@Override
	public DataTypeComponent add(DataType dataType) throws UsrException {
		int rowIndex = getMinIndexSelected();
		if (rowIndex < 0) {
			throw new UsrException("A component must be selected.");
		}
		return replace(rowIndex, dataType);
	}
Gets the original field name within the parent data type for a given row in the editor
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/stackeditor/StackEditorModel.java