diff -u b/js/paragraphs.admin.js b/js/paragraphs.admin.js
--- b/js/paragraphs.admin.js
+++ b/js/paragraphs.admin.js
@@ -11,14 +11,19 @@
     attach: function (context, settings) {
       /** Set content fields to visible when tabs are created. After an action being performed, stay on the same
        * perspective. **/
-      if($(context).find('.paragraphs-tabs-wrapper').find('#behavior').hasClass('is-active')) {
+      if($(context).find('.layout-region-node-main').hasClass('behavior-active')) {
+        $(context).find('.layout-region-node-main').removeClass('content-active');
+        $(context).find('.layout-region-node-main').addClass('behavior-active');
+        $(context).find('.paragraphs-tabs').find('#content').removeClass('is-active');
+        $(context).find('.paragraphs-tabs').find('#behavior').addClass('is-active');
         $('.paragraphs-content').hide();
         $('.paragraphs-behavior').show();
       }
       else {
         /** Activate content tab visually if there is no previously activated tab. */
-        if (!($(context).find('.paragraphs-tabs-wrapper').find('#content').hasClass('is-active'))) {
+        if (!($(context).find('.layout-region-node-main').hasClass('content-active')) && !($(context).find('.layout-region-node-main').hasClass('behavior-active'))) {
           $(context).find('.paragraphs-tabs').find('#content').addClass('is-active');
+          $(context).find('.layout-region-node-main').addClass('content-active');
         }
         $('.paragraphs-content').show();
         $('.paragraphs-behavior').hide();
@@ -30,14 +35,18 @@
         var el = jQuery(this);
         $(context).find('.paragraphs-tabs').find('li').removeClass('is-active');
         el.parent('li').addClass('is-active');
+        $(context).find('.layout-region-node-main').removeClass('behavior-active');
+        $(context).find('.layout-region-node-main').removeClass('content-active');
         $(context).find('.paragraphs-tabs-wrapper').removeClass('is-active');
         $(context).find(el.attr('href')).addClass('is-active');
         /** Show/Hide fields based on current active class. */
         if($(context).find('.paragraphs-tabs-wrapper').find('#content').hasClass('is-active')) {
+          $(context).find('.layout-region-node-main').addClass('content-active');
           $('.paragraphs-content').show();
           $('.paragraphs-behavior').hide();
         }
         if($(context).find('.paragraphs-tabs-wrapper').find('#behavior').hasClass('is-active')) {
+          $(context).find('.layout-region-node-main').addClass('behavior-active');
           $('.paragraphs-content').hide();
           $('.paragraphs-behavior').show();
         }
diff -u b/src/Plugin/Field/FieldWidget/ParagraphsWidget.php b/src/Plugin/Field/FieldWidget/ParagraphsWidget.php
--- b/src/Plugin/Field/FieldWidget/ParagraphsWidget.php
+++ b/src/Plugin/Field/FieldWidget/ParagraphsWidget.php
@@ -1318,7 +1318,7 @@
             }
             if (isset($element[$delta]) && isset($element[$delta]['behavior_plugins'][$plugin_id]) && $form_state->getCompleteForm()) {
               $subform_state = SubformState::createForSubform($element[$delta]['behavior_plugins'][$plugin_id], $form_state->getCompleteForm(), $form_state);
-              if ($item['behavior_plugins'][$plugin_id]) {
+              if (isset($item['behavior_plugins'][$plugin_id])) {
                 $plugin_values->submitBehaviorForm($paragraphs_entity, $item['behavior_plugins'][$plugin_id], $subform_state);
               }
             }
reverted:
--- b/src/Tests/Experimental/ParagraphsExperimentalBehaviorsTest.php
+++ a/src/Tests/Experimental/ParagraphsExperimentalBehaviorsTest.php
@@ -75,13 +75,13 @@
 
     // Create a node with a Paragraph.
     $this->drupalGet('node/add/paragraphed_test');
+    $this->assertFieldByName('field_paragraphs[0][behavior_plugins][test_text_color][text_color]', 'green');
-    $this->assertFieldByName('field_paragraphs[0][subform][test_text_color][text_color]', 'green');
     // Setting a not allowed value in the text color plugin text field.
     $plugin_text = 'green';
     $edit = [
       'title[0][value]' => 'paragraphs_plugins_test',
       'field_paragraphs[0][subform][field_text][0][value]' => 'amazing_plugin_test',
+      'field_paragraphs[0][behavior_plugins][test_text_color][text_color]' => $plugin_text,
-      'field_paragraphs[0][subform][test_text_color][text_color]' => $plugin_text,
     ];
     $this->drupalPostForm(NULL, $edit, t('Save and publish'));
     // Asserting that the error message is shown.
@@ -89,7 +89,7 @@
     // Updating the text color to an allowed value.
     $plugin_text = 'red';
     $edit = [
+      'field_paragraphs[0][behavior_plugins][test_text_color][text_color]' => $plugin_text,
-      'field_paragraphs[0][subform][test_text_color][text_color]' => $plugin_text,
     ];
     $this->drupalPostForm(NULL, $edit, t('Save and publish'));
     // Assert that the class has been added to the element.
@@ -97,21 +97,21 @@
 
     $this->clickLink('Edit');
     // Assert the plugin fields populate the stored values.
+    $this->assertFieldByName('field_paragraphs[0][behavior_plugins][test_text_color][text_color]', $plugin_text);
-    $this->assertFieldByName('field_paragraphs[0][subform][test_text_color][text_color]', $plugin_text);
 
     // Update the value of both plugins.
     $updated_text = 'blue';
     $edit = [
+      'field_paragraphs[0][behavior_plugins][test_text_color][text_color]' => $updated_text,
+      'field_paragraphs[0][behavior_plugins][test_bold_text][bold_text]' => TRUE,
-      'field_paragraphs[0][subform][test_text_color][text_color]' => $updated_text,
-      'field_paragraphs[0][subform][test_bold_text][bold_text]' => TRUE,
     ];
     $this->drupalPostForm(NULL, $edit, t('Save and keep published'));
     $this->assertNoRaw('class="red_plugin_text');
     $this->assertRaw('class="blue_plugin_text bold_plugin_text');
     $this->clickLink('Edit');
     // Assert the plugin fields populate the stored values.
+    $this->assertFieldByName('field_paragraphs[0][behavior_plugins][test_text_color][text_color]', $updated_text);
+    $this->assertFieldByName('field_paragraphs[0][behavior_plugins][test_bold_text][bold_text]', TRUE);
-    $this->assertFieldByName('field_paragraphs[0][subform][test_text_color][text_color]', $updated_text);
-    $this->assertFieldByName('field_paragraphs[0][subform][test_bold_text][bold_text]', TRUE);
 
     // Test plugin applicability. Add a paragraph type.
     $paragraph_type = 'text_paragraph_test';
diff -u b/tests/src/FunctionalJavascript/ParagraphsExperimentalEditPerspectivesUiTest.php b/tests/src/FunctionalJavascript/ParagraphsExperimentalEditPerspectivesUiTest.php
--- b/tests/src/FunctionalJavascript/ParagraphsExperimentalEditPerspectivesUiTest.php
+++ b/tests/src/FunctionalJavascript/ParagraphsExperimentalEditPerspectivesUiTest.php
@@ -25,11 +25,13 @@
    */
   public static $modules = [
     'node',
+    'paragraphs_collection',
     'paragraphs_collection_test',
-    'paragraphs_test',
+    'paragraphs_collection_demo',
     'field',
     'field_ui',
     'block',
+    'link',
   ];
 
   /**
@@ -46,12 +48,16 @@
 
-    $this->loginAsAdmin();
+    $this->loginAsAdmin([
+      'access content overview',
+      'edit any paragraphed_content_demo content'
+    ]);
 
     $page = $this->getSession()->getPage();
-    $this->drupalGet('node/2/edit');;
+    $this->drupalGet('node/3/edit');
     $this->clickLink('Behavior');
-    $style_selector = $page->find('css', 'js-form-item-field-paragraphs-demo-0-behavior-plugins-style-style form-item-field-paragraphs-demo-0-behavior-plugins-style-style');
+    $style_selector = $page->find('css', '.js-form-item-field-paragraphs-demo-1-behavior-plugins-grid-layout-layout');
     $this->assertTrue($style_selector->isVisible());
     $this->clickLink('Content');
     $this->assertFalse($style_selector->isVisible());
   }
+
 }