Bug 142928 Item from library is changed to a report design item after revert to report item
Details: Item from library is changed to a report design item after revert to report item. Setp: 1.New a template. 2.Use a libary contain a label. 3.Drop the label from library explorer into layout. 4.Change the label to template item. 5.Revert the template item to report item. Actual result: The label is become a report item, but a item from library. Please see the attach image. Exception result: The lable is revert a item from library.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/DesignElementHandle.java
* @see #dropAndClear()
	 */
	public void drop( ) throws SemanticException
	{
		DesignElement element = getElement( );
		DesignElement container = element.getContainer( );
		if ( container == null )
			throw new ContentException( element, -1,
					ContentException.DESIGN_EXCEPTION_HAS_NO_CONTAINER );
		int slotID = element.getContainerSlot( );
		assert slotID != -1;
		ContentCommand cmd = new ContentCommand( module, container );
		cmd.remove( element, slotID, true );
	}
	/**
	 * Finds the slot within this element that contains the given element.
	 * 
	 * @param content
	 *            handle to the content element to find
	 * @return The ID of the slot that contains the element, or
	 *         {@link DesignElement#NO_SLOT}if the element is not contained in
	 *         this element.
	 */
	public int findContentSlot( DesignElementHandle content )
	{
		if ( content.getContainer( ).getElement( ) == getElement( ) )
			return content.getElement( ).getContainerSlot( );
		return DesignElement.NO_SLOT;
	}
	/**