Express Checkout credit card not all open popup

[suluh]

I am trying to integrate Express Checkout in my site, with ability for customer to use credit card for payment. I am using OpenCart and have activated Express Checkout according to its documentation.

The PayPal button is successfully displayed with rows of credit card buttons. But only when I click Amex button, it will open a popup window as usual. If I click on other cards, it will add inline form below the buttons, and sometimes the forms not displaying at all, just keep showing loading spinner.

I am still testing my site, only use sandbox for now. I am worried if this behavior is same when I switch to Live site.

Is there a setting to make all credit card button to open in pop up window?

Thanks

[csunyafreemail]

For me when hooking anything on the onShippingChange handler in the JS SDK, it opens the modal, if no event handler hooked, then I get the inline guest checkout. Problem is, the inline checkout does not succeed (fails with Internal Error 500 on PayPal side!), plus there is no price overview like in the modal (literally the price is not displayed at all in the inline guest flow, wtf :D).
The thing is, there is zero info on what decides which flow, modal or inline is triggered. It feels like A/B testing or lottery a bit : (
Btw in my case - in contrast to most people out there - I would actually prefer the inline version, as it fits nicely with my design, but I also need to listen to shipping changes.