Merge branch '8.x-1.x' of github.com:drupalcommerce/commerce_paypal into 2843999-ipn-handler

Author: vasike

src/Plugin/Commerce/PaymentGateway/ExpressCheckout.php

@@ -191,6 +191,7 @@ public function validateConfigurationForm(array &$form, FormStateInterface $form
       $this->configuration['api_password'] = $values['api_password'];
       $this->configuration['signature'] = $values['signature'];
       $this->configuration['solution_type'] = $values['solution_type'];
+      $this->configuration['mode'] = $values['mode'];
 
       $response = $this->doRequest([
         'METHOD' => 'GetBalance',