diff --git a/demos/form/form.php b/demos/form/form.php
index 25c27402d0..80dc4746e8 100644
--- a/demos/form/form.php
+++ b/demos/form/form.php
@@ -56,13 +56,16 @@
 $group->addControl('surname');
 $group->addControl('gender', [Form\Control\Dropdown::class, 'values' => ['Female', 'Male']]);
 
+$accordionLayout = $form->layout->addSubLayout([Form\Layout\Section\Accordion::class]);
+$details = $accordionLayout->addSection('Validating Field in Accordion');
+
 // testing 0 value
 $values = [0 => 'noob', 1 => 'pro', 2 => 'dev'];
 $form->addControl('description', [Form\Control\Textarea::class])->set(0);
 $form->addControl('no_description', [Form\Control\Textarea::class])->set(null);
 $form->addControl('status_optional', [Form\Control\Dropdown::class, 'values' => $values]);
-$form->addControl('status_string_not-nullable', [Form\Control\Dropdown::class], ['type' => 'string', 'values' => $values, 'nullable' => false]);
-$form->addControl('status_integer_not-nullable', [Form\Control\Dropdown::class], ['type' => 'integer', 'values' => $values, 'nullable' => false]);
+$details->addControl('status_string_not-nullable', [Form\Control\Dropdown::class], ['type' => 'string', 'values' => $values, 'nullable' => false]);
+$details->addControl('status_integer_not-nullable', [Form\Control\Dropdown::class], ['type' => 'integer', 'values' => $values, 'nullable' => false]);
 $form->addControl('status_string_required', [Form\Control\Dropdown::class], ['type' => 'string', 'values' => $values, 'required' => true]);
 $form->addControl('status_integer_required', [Form\Control\Dropdown::class], ['type' => 'integer', 'values' => $values, 'required' => true]);
 
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 20e7b22418..07aef3bd83 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -87,6 +87,9 @@ parameters:
         -
             path: 'demos/form/form.php'
             message: '~^Call to an undefined method Atk4\\Ui\\JsChain::checkbox\(\)\.$~'
+        -
+            path: 'demos/form/form.php'
+            message: '~^Call to an undefined method Atk4\\Ui\\Form\\Layout::addSection\(\)\.$~'
         -
             path: 'demos/form/form2.php'
             message: '~^Call to an undefined method Atk4\\Ui\\Form\\Control::addAction\(\)\.$~'
diff --git a/src/AccordionSection.php b/src/AccordionSection.php
index 79f1342c88..7c84487f60 100644
--- a/src/AccordionSection.php
+++ b/src/AccordionSection.php
@@ -22,12 +22,17 @@ class AccordionSection extends View
     /** @var string */
     public $icon = 'dropdown';
 
+    /** @var string */
+    public $warningIcon = 'exclamation circle';
+
     protected function renderView(): void
     {
         parent::renderView();
 
         $this->template->set('icon', $this->icon);
 
+        $this->template->set('warningIcon', $this->warningIcon);
+
         if ($this->title) {
             $this->template->set('title', $this->title);
         }
diff --git a/src/Form.php b/src/Form.php
index 248dc88618..f843b52eb8 100644
--- a/src/Form.php
+++ b/src/Form.php
@@ -260,6 +260,11 @@ public function onSubmit(\Closure $callback)
                 $response = [];
                 foreach ($e->errors as $field => $error) {
                     $response[] = $this->error($field, $error);
+
+                    // If field inside Accordion section does not validate, open first AccordionSection
+                    if ($this->getControl($field)->getOwner()->getOwner() instanceof \Atk4\Ui\AccordionSection) {
+                        $response[] = $this->getControl($field)->getOwner()->getOwner()->getOwner()->js(true)->find('i.icon.atk-panel-warning.exclamation.circle')->addClass('atk-visible');
+                    }
                 }
 
                 return $response;
diff --git a/template/accordion-section.html b/template/accordion-section.html
index fdfd8514da..5b3ebe3711 100644
--- a/template/accordion-section.html
+++ b/template/accordion-section.html
@@ -1,5 +1,5 @@
 
-<div class="title" id="{$_id}"><i class="{$icon} icon"></i>{title}Title{/}</div>
+<div class="title" id="{$_id}"><i class="{$icon} icon"></i><i class="atk-panel-warning {$warningIcon} icon"></i>{title}Title{/}</div>
 <div class="content ui basic segment" data-path="{$path}" style="min-height: 60px">
   <div id="{$itemId}">{$Content}</div>
 </div>
diff --git a/template/accordion-section.pug b/template/accordion-section.pug
index 13cbf6bc53..7b0df518b9 100644
--- a/template/accordion-section.pug
+++ b/template/accordion-section.pug
@@ -1,5 +1,6 @@
 div(id="{$_id}" class="title")
     i(class="{$icon} icon")
+    i(class="atk-panel-warning {$warningIcon} icon")
     | {title}Title{/}
 div(class="content ui basic segment", data-path="{$path}", style="min-height: 60px")
     div(id="{$itemId}")