replace $_SESSION with sqgetGlobalVar

include/load_prefs.php

@@ -18,7 +18,9 @@ require_once(SM_PATH . 'functions/prefs.php');
 require_once(SM_PATH . 'functions/plugin.php');
 require_once(SM_PATH . 'functions/constants.php');
 
-$username = ( !isset($_SESSION['username']) ? '' : $_SESSION['username'] );
+if( ! sqgetGlobalVar('username', $username, SQ_SESSION) ) {
+    $username = '';
+}
 
 $custom_css = getPref($data_dir, $username, 'custom_css', 'none' );