Bug 176436 Charts Imported from Libraries do not update when libraries change
During a live presentation of BIRT at EclipseCon, we came across a rather embarassing issue. When charts are included in a library, and imported into a report design from a library, any changes to the library instance of the chart do not reflect in the report itself.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/GroupElementHandle.java
*         are handles to the common properties, type of them is
	 *         <code>GroupPropertyHandle</code>
	 */
	abstract public Iterator visiblePropertyIterator( );
	/**
	 * Checks whether a property is visible in the property sheet. The visible
	 * property is visible in all <code>elements</code>.
	 * 
	 * @param propName
	 *            the property name
	 * @return <code>true</code> if it is visible. Otherwise
	 *         <code>false</code>.
	 */
	abstract protected boolean isPropertyVisible( String propName );
	/**
	 * Clears values of all common properties(except the extends property) for
	 * the given collection of elements. Clearing a property removes any value
	 * set for the property on this element. After this, the element will now
	 * inherit the property from its parent element, style, or from the default
	 * value for the property.
	 * 
	 * @throws SemanticException
	 *             if the property is not defined on this element
	 */
	abstract public void clearLocalProperties( ) throws SemanticException;
	/**
	 * Returns <code>true</code> if each of the given collection of element
	 * extends has a parent. Returns <code>false</code> otherwise. If the
	 * collection has no elements, also return <code>false</code>
	 *