Using the Express Checkout flow for Digital Goods, the user is forwarded into a Minibrowser window to login with their credentials and confirm the payment. When the user clicks Cancel in the Minibrowser or confirms the payment, they are redirected to the cancel or return URLs provided during the Paypal Checkout and from there I can redirect them in the parent window to the fulfillment page as described here:
https://developer.paypal.com/docs/classic/express-checkout/digital-goods/ClosingWindow/
However if the user just closes the Minibrowser window itself, the Cancel URL is never opened and the redirect in the parent window does not happen. How can I handle the case that a user closes the Minibrowser so I can send them to the cancel page?
Update
The cancel URL is called on window close inside the parent window, if I set expType to 'light' in Javascript. However, it is not called if I set expType to 'instant', which is the desired one. Is this a bug?