Bug 146159 [Regression]Changing font operation doesn't work other than the first time
Description: The first time changing operation can work well. However, Change it again, it won't work. Steps: 1.Insert lable/text to layout or master page 2.Change the font from serif to cursive, it works well 3.Change the font again Result: The action doesn't work Additional infor: build number:200606080632
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
* Get the containable element type list of give slot handle
	 * 
	 * @param slotHandle
	 */
	public static List getElementSupportList( SlotHandle slotHandle )
	{
		return getElementSupportList( slotHandle.getElementHandle( ),
				slotHandle.getSlotID( ) );
	}
	/**
	 * Gets the support list of the given parent element. The slotID is decided
	 * by the parent element.
	 * 
	 * @param parent
	 *            the parent element
	 * @return the the support list of the element
	 */
	public static List getElementSupportList( DesignElementHandle parent )
	{
		int slotID = -1;
		if ( parent instanceof MasterPageHandle )
		{
			slotID = GraphicMasterPageHandle.CONTENT_SLOT;
		}
		return getElementSupportList( parent, slotID );
	}
	/**
	 * Find the position of the element. If the element is null, the position is
	 * last
	 *