I have implemented payments using PayPal IPN checkout.
Is there any way to make PayPal checkout window with "Pay with PayPal Account" Panel open by default on the right side? Currently, it always shows "Pay with credit or debit card" panel.

2 Answers
There's no real way to control that window. It depends entirely on PayPal and what they choose to feed the user. Keep in mind, most people want the credit card portion open by default (I've heard far more people ask for the exact opposite of your question). Some users may even be presented with Bill Me Later options.
If it's that important, you could always integrate express-checkout directly. Requires some programming on your part but does not offer any credit card options. Express Checkout is free to use.
If you are using the simple PayPal buttons then you don't have the control over this . But if you use the PayPal Express Checkout you can control this behavior by passing the one variable in the Set Express Checkout API call :
LANDINGPAGE = Billing ( for opening up the credit card option) or LANDINGPAGE = Login ( for opening up the PayPal account option )
You can refer the below link for the express checkout integration :