-- At PayPal --The shopper _must_ press the "Continue" button at PayPal's "You Made A Payment"page. Clicking on the "Continue" button tells PayPal to notify the shopping cartthat the order is valid and to expect confirmation when the shopper's payment goesthrough.-- Message to add if there is a problem -- In the store configuration, add to the "Message above Comment Box" message ('Advanced Level'->'Order Total Options') a message stating that "If you wish to pay with PayPal, please go through all of the pages until you come to our ([put merchant's name here]) 'thank you' page for proper order processing."