Bug 142137 Style name can't be changed to None in Property Editor after delete the style
Steps to reproduce: 1.New a style named "S1", apply it on a label 2.Delete "S1" 3.Switch to Property Editor, change label style to None Expected result: Style is changed to None Actual result: Style is still "S1" till change it with context menu
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/StyleCommand.java
*/
	protected void setStyleRefValue( ElementRefValue refValue )
			throws StyleException
	{
		if ( refValue == null && element.getStyle( ) == null )
			return;
		doSetStyleRefValue( refValue );
	}
	/**
	 * Does the work to set the new style with the given
	 * <code>newStyleValue</code>.
	 * 
	 * @param newStyleValue
	 *            the validated <code>ElementRefValue</code>
	 */
	private void doSetStyleRefValue( ElementRefValue newStyleValue )
			throws StyleException
	{
		if ( newStyleValue != null && !newStyleValue.isResolved( ) )
			throw new StyleException( element, newStyleValue.getName( ),
					StyleException.DESIGN_EXCEPTION_NOT_FOUND );
		if ( newStyleValue != null && newStyleValue.isResolved( )
				&& newStyleValue.getElement( ) == element.getStyle( ) )
			return;
		
		StyledElement obj = (StyledElement) element;
		StyleRecord record = new StyleRecord( obj, newStyleValue );
		getActivityStack( ).execute( record );
	}
}