Optional extra products on add to cart form We're trying to have it so that on a product display there are optional extras which can be added all at the same time as the main product by selecting checkboxes. These products are optional extras which are product specific.

We have tried the Commerce Product Add On module but it breaks with an ajax error when there is more than one main product variation and another option is selected on the product display front end.

We are trying to debug the error but we are also wondering if this can be created using something which already exists such as views bulk operations and rules. Any help would be much appreciated!
There is for example Commerce add to cart extras:


  This module provides alternative ways of adding products to cart.
  
  The initial version provides a views field handler ("Commerce Product:
  Quantity input field") that relies on the Views Form API (a part of
  Views 3 since RC1) to output a quantity textfield that turns the view
  into an add to cart form. The default quantity can be configured, and
  only products with a quantity larger than 0 are added to the cart.


Also, you can find 2 approaches (VBO + Rules, and custom VBO action) at Add multiple products to cart with VBO.