Bug 122850 Table/list should not be able to be inserted in Master Page mode.
Description: Table/list should not be able to be inserted in Master Page mode. Steps to reproduce: 1. New a report and transfer to Master Page mode. 2. New a datasource and dataset 3. Drag a list/table to page header/footer, bind it to dataset and drag some columns inside. 4. Save and preview Expected result: Insert list/table item in master page should be forbidden. Actual result: They are allowed and preview showed "undefine" in page
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/util/ModelUtil.java
String extensionId = (String) source
					.getProperty( IOdaExtendableElementModel.EXTENSION_ID_PROP );
			destination.getElement( ).setProperty(
					IOdaExtendableElementModel.EXTENSION_ID_PROP, extensionId );
		}
		else
		if ( source.getElement( ) instanceof IExtendedItemModel )
		{
			String extensionId = (String) source
					.getProperty( IExtendedItemModel.EXTENSION_NAME_PROP );
			destination.getElement( ).setProperty(
					IExtendedItemModel.EXTENSION_NAME_PROP, extensionId );
		}
		else
		{
			assert false;
		}
	}
	/**
	 * Clone the structure list, a list value contains a list of
	 * <code>IStructure</code>.
	 * 
	 * @param list
	 *            The structure list to be cloned.
	 * @return The cloned structure list.
	 */
	public static ArrayList cloneStructList( ArrayList list )
	{
		if ( list == null )
			return null;