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
* Clears the value of a property. Clearing a property removes any value set
	 * for the property on this element. After this, the element will now
	 * inherit the property from its parent element, style, or from the default
	 * value for the property.
	 * 
	 * @param propName
	 *            the name of the property to clear.
	 * @throws SemanticException
	 *             if the property is not defined on this element
	 */
	public void clearProperty( String propName ) throws SemanticException
	{
		setProperty( propName, null );
	}
	/**
	 * Clears values of all properties. Clearing a property removes any value
	 * set for the property on this element. After this, the element will now
	 * inherit the property from its parent element, style, or from the default
	 * value for the property.
	 * 
	 * @throws SemanticException
	 *             if the property is not defined on this element
	 */
	public void clearAllProperties( ) throws SemanticException
	{
		List props = getDefn( ).getProperties( );
		for ( int i = 0; i < props.size( ); i++ )
		{
			PropertyDefn propDefn = (PropertyDefn) props.get( i );
			String propName = propDefn.getName( );