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
* Returns the shared style, if any, as a style handle. A shared style is a
	 * style that defines in the "styles" slot of the report design.
	 * 
	 * @return a handle to the shared style used by this element. Returns null
	 *         if the style is not set, or if the element does not support a
	 *         style.
	 * 
	 * @see #setStyle(SharedStyleHandle)
	 * @see #setStyleElement(StyleElement)
	 * @see #setStyleName(String)
	 */
	public SharedStyleHandle getStyle( )
	{
		DesignElement style = getElement( ).getStyle( module );
		if ( style == null )
			return null;
		return (SharedStyleHandle) style.getHandle( module );
	}
	/**
	 * Sets the name of the shared style for this element.
	 * 
	 * @param name
	 *            the name of the shared style. If <code>null</code>, then
	 *            the shared style name is cleared.
	 * @throws StyleException
	 *             If the name is not valid, or if this element does not support
	 *             a style.
	 * 
	 * @see #getStyle()
	 */