Issue To Paypal Module

[missamoresg]

I have added paypal payment module to my website PS could, i also have 2 type of shipment, One free shipping and another one is with extra charges, By default the shipping will be Free shipping. When i try out the checkout, i notice if i dont change the shipping method and when click Paypal checkout method it works fine. If i change the shipment method from default free shipping to paid shipped and tried to do Paypal checkout, It doesnt work means when i click on the Paypal checkout nothing happens. I not notice if go to another page and come back then paypal is working good, I need advise on this