The fix is a simple as:
$action = isset($_GET['action']) ? $_GET['action'] : null;
if ( !get_site_option( 'dm_remote_login' ) || $action == 'logout' || isset( $_GET[ 'loggedout' ] ) ) {
return false;
}
Do you mind checking that into SVN, Ron?
Also, I find the lack of development activity on this plugin a bit worrying. Any plans on releasing a new stable version soon that is guaranteed to work seamlessly with WP 4.0?