<ul><li>Initialized <code>$activeclass = ''</code> before conditional block in toolbar.php — was only set inside <code>if (!isset($_REQUEST['action']))</code> but used unconditionally on breadcrumb echo lines</li><li>Wrapped both <code>$_REQUEST['step']</code> accesses (webmod branch line ~389 and action branch line ~399) with <code>isset()</code> guards — step is optional and not present on routes like <code>?action=details&templateid=...</code></li><li>Triggered by: <code>/platform/administration/templates/?action=details&templateid=10054</code></li></ul>