diff --git a/web/js/components/app-tabs.js b/web/js/components/app-tabs.js
index 697a3e1..7adf017 100644
--- a/web/js/components/app-tabs.js
+++ b/web/js/components/app-tabs.js
@@ -219,6 +219,7 @@ export function initTabs(root = document, config = {}) {
 
     const form = container.closest('form');
     if (form instanceof HTMLFormElement) {
+      const formId = String(form.id || '').trim();
       const inputSelector = 'input,select,textarea';
 
       const clearInvalidMarkers = () => {
@@ -251,7 +252,12 @@ export function initTabs(root = document, config = {}) {
       };
 
       const onFormClickCapture = (event) => {
-        const trigger = event.target.closest('button, [type="submit"]');
+        const target = event.target;
+        if (!(target instanceof Element)) {
+          return;
+        }
+
+        const trigger = target.closest('button, [type="submit"]');
         if (!trigger) {
           return;
         }
@@ -275,7 +281,7 @@ export function initTabs(root = document, config = {}) {
 
         const invalidFields = form.querySelectorAll(inputSelector);
         for (const field of invalidFields) {
-          if (!belongsToForm(field) || field.disabled || field.checkValidity()) {
+          if (!belongsToForm(field, form) || field.disabled || field.checkValidity()) {
             continue;
           }
           let element = field.parentElement;
@@ -309,7 +315,7 @@ export function initTabs(root = document, config = {}) {
           return;
         }
         const fields = panel.querySelectorAll(inputSelector);
-        if (Array.from(fields).every((field) => !belongsToForm(field) || field.disabled || field.checkValidity())) {
+        if (Array.from(fields).every((field) => !belongsToForm(field, form) || field.disabled || field.checkValidity())) {
           tab.classList.remove('has-invalid');
         }
       };