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
{
		SlotHandle slotHandle = getSlot( slotId );
		if ( slotHandle != null )
			slotHandle.add( child );
	}
	/**
	 * Returns the methods defined on the element definition.
	 * 
	 * @return List contains the methods.
	 * 
	 */
	public List getMethods( )
	{
		return getElement( ).getDefn( ).getMethods( );
	}
	/**
	 * Sets a bunch of property values on the element. If this operation should
	 * be treated as a whole, execution should be in a transaction.
	 * 
	 * @param properties
	 *            a Map store the property values keyed by the property name.
	 * @throws SemanticException
	 *             if the property is undefined on the element or the value is
	 *             invalid.
	 * @see #setProperty(String, Object)
	 */
	public void setProperties( Map properties ) throws SemanticException
	{
		if ( properties == null )
			return;