Resolved gh-418 by adding an on before cancel custom script area to the admin view.

admin/sql/updates/mysql/2.9.18.sql

@@ -0,0 +1,3 @@
+ALTER TABLE `#__componentbuilder_admin_view` ADD `add_php_before_cancel` TINYINT(1) NOT NULL DEFAULT 0 AFTER `add_php_batchmove`;
+
+ALTER TABLE `#__componentbuilder_admin_view` ADD `php_before_cancel` MEDIUMTEXT NOT NULL AFTER `php_batchmove`;