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
{
		DesignElement element = getElement( );
		ElementPropertyDefn propDefn = element.getPropertyDefn( propName );
		if ( propDefn == null )
			return null;
		return new PropertyHandle( this, propDefn );
	}
	/**
	 * Returns a user-defined property handle for a top-level property. A
	 * top-level property is a property that defines on an element.
	 * 
	 * @param propName
	 *            the name of the property to get
	 * @return the user property definition handle, or <code>null</code> if
	 *         the no property exists with the given name or it is not a
	 *         user-defined property.
	 */
	public UserPropertyDefnHandle getUserPropertyDefnHandle( String propName )
	{
		DesignElement element = getElement( );
		ElementPropertyDefn propDefn = element.getPropertyDefn( propName );
		if ( propDefn == null )
			return null;
		if ( propDefn.isUserProperty( ) )
		{
			return new UserPropertyDefnHandle( this,
					(UserPropertyDefn) propDefn );
		}
		return null;
	}