diff --git a/buttoncustomizations.php b/buttoncustomizations.php
index 1b4534b662141f1bbc431e22759965d5b5881042..e78d8011e6074f9455fd9534702380cc2bab27b4 100644
--- a/buttoncustomizations.php
+++ b/buttoncustomizations.php
@@ -10,7 +10,7 @@ require_once 'buttoncustomizations.civix.php';
  */
 function buttoncustomizations_civicrm_buildForm($formName, &$form) {
   // Change the button on contribution pages to read "Confirm Payment".
-  if ($formName == CRM_Contribute_Form_Contribution_Main) {
+  if ($formName == 'CRM_Contribute_Form_Contribution_Main') {
     $buttonGroup = $form->getElement('buttons');
     $buttons = $buttonGroup->getElements();
     $submitButton = $buttons[0];