i am using Version 3.13 | Enterprise.. i noticed 2 problems :
1- the subject defined on the function setSubject on the
$crud->setSubject(‘Customer’, ‘Customers’);
if you make 2 or 3 cruds the last subject for last crud will be applied on all above subjects on edit and add pop up forms..
on the image you will find the subject for all cruds shown as last crud subject on edit and add forms.
2- on the working example on the link: Multiple Grids | Grocery CRUD - A PHP CRUD Generator Library
it have a mistake on line:
$output2 = $crud->render();
it have to be : $output2 = $crud2->render(); //crud2 not crud

