Bug 155943 "Restore Properties" is always enabled for extended chart
Steps to reproduce: 1.New a report, includes a library, extends lib.chart 2.Choose the chart Expected result: "Restore Properties" is disabled untill set/change any local properties for the chart Actual result: "Restore Properties" is always enabled
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/GroupElementHandle.java
}
	/**
	 * Returns the list that contains the group of design elements. Contents of
	 * it is <code>DesignElementHandle</code>
	 * 
	 * @return the list that contains the group of design elements.
	 */
	abstract public List getElements( );
	/**
	 * Returns the module.
	 * 
	 * @return the module
	 */
	abstract public Module getModule( );
	/**
	 * Returns the handle of module.
	 * 
	 * @return the handle of module
	 */
	abstract public ModuleHandle getModuleHandle( );
	/**
	 * Indicates that if the given elements are of the same definition. Elements
	 * are considered of same type if their element definitions are identical.
	 * <p>
	 * If elements have different definitions. Even the same element type, the
	 * return value is <code>false</code>. For example, if the list contains
	 * an <code>OdaDataSource</code> and a <code>OdaDataSource</code>, this
	 * method returns <code>false</code>.
	 * 
	 * @return <code>true</code> if the given elements are of the same type;