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
* @throws StyleException
	 *             if this element does not support a style.
	 * @see #getStyle()
	 */
	public void setStyle( SharedStyleHandle style ) throws StyleException
	{
		if ( style == null )
			setStyleElement( null );
		else
			setStyleElement( (StyleElement) style.getElement( ) );
	}
	/**
	 * Returns a handle to work with the style properties of this element. Use a
	 * style handle to work with the specific getter/setter methods for each
	 * style property. The style handle is not necessary to work with style
	 * properties generically.
	 * <p>
	 * Note a key difference between this method and the
	 * <code>getStyle( )</code> method. This method returns a handle to the
	 * <em>this</em> element. The <code>getStyle( )</code> method returns a
	 * handle to the shared style, if any, that this element references.
	 * 
	 * @return a style handle to work with the style properties of this element.
	 *         Returns <code>null</code> if this element does not have style
	 *         properties.
	 */
	public StyleHandle getPrivateStyle( )
	{
		if ( getDefn( ).hasStyle( ) )
			return new PrivateStyleHandle( module, getElement( ) );