diff --git a/plugins/operation_types/action.class.php b/plugins/operation_types/action.class.php
index 2d40ec8..336fd25 100644
--- a/plugins/operation_types/action.class.php
+++ b/plugins/operation_types/action.class.php
@@ -106,7 +106,7 @@ class ViewsBulkOperationsAction extends ViewsBulkOperationsBaseOperation {
    * @param $form_state
    *   An array containing the current state of the form.
    */
-  public function formSubmit($form, $form_state) {
+  public function formSubmit($form, &$form_state) {
     $submit_callback = $this->operationInfo['callback'] . '_submit';
     $this->formOptions = $submit_callback($form, $form_state);
   }
diff --git a/plugins/operation_types/base.class.php b/plugins/operation_types/base.class.php
index 053bb9f..433e085 100644
--- a/plugins/operation_types/base.class.php
+++ b/plugins/operation_types/base.class.php
@@ -127,7 +127,7 @@ abstract class ViewsBulkOperationsBaseOperation {
    * @param $form_state
    *   An array containing the current state of the form.
    */
-  abstract function formSubmit($form, $form_state);
+  abstract function formSubmit($form, &$form_state);
 
   /**
    * Returns whether the selected entities should be aggregated