Q: Why does 2-finger swipe right close my internet app (Shutterfly)?  Can I get it back?

I have a Macbook Pro, with OSX  version 10.8.5.  Processor is 2.9 GHz Intel Core i7. Memory is 8GB 1600 MHz DDR3.

When I am on the internet (Shutterfly) and accidentally sweep right with two fingers, the whole app slides off the right side of the screen and disappears.  This cannot be undone with a two-finger sweep left (nothing comes over). 

There is a warning message asking if you really want to leave the page, and if you leave page, you can lose your information.  It offers the options: 

     - to "Stay on page" (if you do that, the screen stays blank and will not repopulate) or 

     - to "Leave Page" (if you do that, you go back to the generic My Shutterfly page, and all changes you made to your scrapbook after saving are gone). 

It seems the warning message is TOO LATE, because by then it has already deleted/lost all my information. 

Why is this warning message happening after the information is gone?  How can I get this screen back?  Or how can I prevent this from happening (other than just trying not to swipe right at all or saving every 2 minutes)?

Thank you for any help you could provide.