src/org/tiefaces/components/websheet/chart/ChartHelper.java
private String getChartIdFromParent(final XSSFChart chart,
			final String sheetName) {
		if (chart.getParent() != null) {
			for (RelationPart rp : chart.getParent().getRelationParts()) {
				if (rp.getDocumentPart() == chart) {
					return sheetName + "!" + rp.getRelationship().getId();
				}
			}
		}
		return null;
	}
private String getChartIdFromParent(final XSSFChart chart,
			final String sheetName) {
		if (chart.getParent() != null) {
			for (RelationPart rp : chart.getParent().getRelationParts()) {
				if (rp.getDocumentPart() == chart) {
					return sheetName + "!" + rp.getRelationship().getId();
				}
			}
		}
		return null;
	}
Gets the chart id from parent.

@param chart
the chart
@param sheetName
the sheet name
@return the chart id from parent