src/org/tiefaces/components/websheet/service/WebSheetLoader.java
private void clearWorkbook() {
		parent.setFormulaEvaluator(null);
		parent.setDataFormatter(null);
		parent.setSheetConfigMap(null);
		parent.setTabs(null);
		parent.getSerialDataContext().setDataContext(null);
		parent.setPicturesMap(null);
		parent.setHeaderRows(null);
		parent.setBodyRows(null);
		parent.setWb(null);
		parent.getHeaderRows().clear();
		parent.getBodyRows().clear();
		parent.getCharsData().getChartsMap().clear();
		parent.getCharsData().getChartDataMap().clear();
		parent.getCharsData().getChartAnchorsMap().clear();
		parent.getCharsData().getChartPositionMap().clear();
		parent.getCellAttributesMap().clear();
	}
private void clearWorkbook() {
		parent.setFormulaEvaluator(null);
		parent.setDataFormatter(null);
		parent.setSheetConfigMap(null);
		parent.setTabs(null);
		parent.getSerialDataContext().setDataContext(null);
		parent.setPicturesMap(null);
		parent.setHeaderRows(null);
		parent.setBodyRows(null);
		parent.setWb(null);
		parent.getHeaderRows().clear();
		parent.getBodyRows().clear();
		parent.getCharsData().getChartsMap().clear();
		parent.getCharsData().getChartDataMap().clear();
		parent.getCharsData().getChartAnchorsMap().clear();
		parent.getCharsData().getChartPositionMap().clear();
		parent.getCellAttributesMap().clear();
	}
Clear workbook.