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
/**
	 * If property is shared by the group of elements, return the corresponding
	 * <code>GroupPropertyHandle</code>, otherwise, return <code>null</code>.
	 * 
	 * @param propName
	 *            name of the property needs to be handled.
	 * @return If the property is a common property among the elements, return
	 *         the corresponding <code>GroupPropertyHandle</code>; Otherwise
	 *         return <code>null</code>.
	 */
	abstract public GroupPropertyHandle getPropertyHandle( String propName );
	/**
	 * If the given property is a common property, value will be returned as a
	 * string if all values within the group of elements are equal. If the
	 * property is not a common property, return <code>null</code>.
	 * 
	 * @param propName
	 *            name of the property.
	 * @return the value as a string if the property is a common property and
	 *         all the elements have the same value. Return null if the property
	 *         is not a common property or elements have different values for
	 *         this property.
	 * @see GroupPropertyHandle#getStringValue()
	 */
	public final String getStringProperty( String propName )
	{
		GroupPropertyHandle propHandle = getPropertyHandle( propName );
		if ( propHandle == null )
			return null;
		return propHandle.getStringValue( );