upButton.setEnabled( !selection.isEmpty() );
downButton.setEnabled( !selection.isEmpty() );
if ( !selection.isEmpty() )
{
InterceptorEnum interceptor = ( InterceptorEnum ) selection.getFirstElement();
upButton.setEnabled( interceptors.indexOf( interceptor ) != 0 );
downButton.setEnabled( interceptors.indexOf( interceptor ) != ( interceptors.size() - 1 ) );
}
}