Bug 120317 Set "dimension" property to 3D in "properties" view, error appears in layout editor.
Description: Set "dimension" property to 3D in "properties" view, error appears in layout editor. Steps to reproduce: 1. Add a 2D chart in property editor. 2. Set its dimension property to "three-dimension" in properties view. 3. Error appears in chart.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/extension/PeerExtensibilityProvider.java
* Tests whether the property is the extension property which holds the
	 * serialized XML value for extension model properties. The property type
	 * should be XML.
	 * 
	 * @param propName
	 *            name of the property to check
	 * @return true if the property is XML type and holds the serialized XML
	 *         value for extension model properties, otherwise false
	 */
	public boolean isExtensionXMLProperty( String propName )
	{
		ExtensionElementDefn extDefn = getExtDefn( );
		if ( extDefn != null )
		{
			IPropertyDefn propDefn = extDefn.getProperty( propName );
			if ( propDefn != null
					&& PropertyType.XML_TYPE == propDefn.getTypeCode( ) )
				return true;
		}
		return false;
	}
	/**
	 * Copies the extension values and extension element instance, which
	 * implements <code>IReportItem</code>.
	 * 
	 * @param source
	 *            the source peer extensibility provider
	 */
	public void copyFrom( PeerExtensibilityProvider source )
	{