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/api/validators/TableHeaderContextContainmentValidator.java
* <code>ListingItem</code>.
	 * 
	 * @param element
	 *            the element to check
	 * 
	 * @return <code>true</code> if the <code>element</code> recursively
	 *         contains a <code>ListingItem</code>. Otherwise
	 *         <code>false</code>.
	 */
	private static boolean containsListingElement( DesignElement element )
	{
		if ( element instanceof ListingElement )
			return true;
		
		int count = element.getDefn( ).getSlotCount( );
		for ( int i = 0; i < count; i++ )
		{
			Iterator iter = element.getSlot( i ).iterator( );
			while ( iter.hasNext( ) )
			{
				DesignElement e = (DesignElement) iter.next( );
				if ( e instanceof ListingElement )
					return true;
				if ( containsListingElement( e ) )
					return true;
			}
		}
		return false;
	}
}