Issue #3293152 by bbombachini, VladimirAus: Trying to access array offset on...

Issue #3293152 by bbombachini, VladimirAus: Trying to access array offset on value of type null in Drupal\campaignmonitor\Form\CampaignMonitorListSettingsForm->buildForm()

src/Form/CampaignMonitorListSettingsForm.php

@@ -284,7 +284,7 @@ class CampaignMonitorListSettingsForm extends ConfigFormBase {
       }
       foreach ($options as $key => $option) {
         $form[$form_key]['CustomFields'][$key]['#attributes']['class'][] = 'draggable';
-        $form[$form_key]['CustomFields'][$key]['#weight'] = $defaults['CustomFields'][$key]['weight'];
+        $form[$form_key]['CustomFields'][$key]['#weight'] = $defaults['CustomFields'][$key]['weight'] ?? 0;
         $form[$form_key]['CustomFields'][$key]['selected'] = [
           '#type' => 'checkbox',
           '#title' => $option,