code/extensions/EditLockControllerExtension.php
public function updateItemEditForm($form)
    {
        if ($record = $form->getRecord()) {
            $form = $this->updateForm($form, $record);
        }
    }
public function updateItemEditForm($form)
    {
        if ($record = $form->getRecord()) {
            $form = $this->updateForm($form, $record);
        }
    }
Extension hook for GridFieldDetailForm_ItemRequest