Bad user experience logic

I have reported some problems with my clienst. I think that logic of this plugin is bad – correct me if I am wrong. Here it is a scenario:
1. User is in the checkout, he/she doesn’t fill required address fields
2. He/she clicks on PayPal or Credit card payment, and accomplishes payment in the javascript PopUp or external Braintree code embedd into webstor.
3. After that He/she might think that it was already paid, so order has been finished, but WAIT! He/she needs to click a button PLACE ORDER to finish checkout and place order
4. User doesn’t understand this process, which seems confused for ~10% of my clients

Suggested fix?
1. I think that I am gonna first fade in css Payments html block, until user fills all requried address fields
2. After succesfull “paymenet” via Braintree, there should be some kind of response message saying: “Now you should place order to complete”