diff -u b/src/Plugin/Field/FieldWidget/InlineParagraphsWidget.php b/src/Plugin/Field/FieldWidget/InlineParagraphsWidget.php
--- b/src/Plugin/Field/FieldWidget/InlineParagraphsWidget.php
+++ b/src/Plugin/Field/FieldWidget/InlineParagraphsWidget.php
@@ -585,9 +585,16 @@
       }
 
       if ($item_mode == 'edit') {
+        $element['subform']['paragraph-content'] = [
+          '#type' => 'container',
+        ];
+        $element['subform']['paragraph-behavior'] = [
+          '#type' => 'container',
+        ];
         $display->buildForm($paragraphs_entity, $element['subform'], $form_state);
         foreach (Element::children($element['subform']) as $field) {
           if ($paragraphs_entity->hasField($field)) {
+            $element['subform'][$field]['#group'] = 'paragraph-content';
             $translatable = $paragraphs_entity->{$field}->getFieldDefinition()->isTranslatable();
             if ($translatable) {
               $element['subform'][$field]['widget']['#after_build'][] = [
@@ -601,17 +608,9 @@
         // Build the behavior plugins fields.
         $paragraphs_type = $paragraphs_entity->getParagraphType();
         if ($paragraphs_type) {
-          $element['behavior_plugins'] = [
-            '#type' => 'container',
-            '#attributes' => [
-              'class' => [
-                'paragraphs-behavior',
-              ],
-            ],
-          ];
           foreach ($paragraphs_type->getEnabledBehaviorPlugins() as $plugin_id => $plugin) {
-            $element['behavior_plugins'][$plugin_id] = [];
-            $element['behavior_plugins'][$plugin_id] = $plugin->buildBehaviorForm($paragraphs_entity);
+            $element['subform'][$plugin_id] = $plugin->buildBehaviorForm($paragraphs_entity);
+            $element['subform'][$plugin_id]['#group'] = 'paragraph-behavior';
           }
         }
       }