why new execution key is assigned when "browse" hotel is clicked in booking-faces

[springnewboy]

hi,
I have a question about webflow execution key assignment mechanism. The question is as followed. When I run the webflow 2.3 "booking-faces" example, I search the hotels and go to the 5th page of the search result ,and at this time I got "execution=e1s2" url. Then I browse a hotel detail info in a url with "execution=e1s3". And when I click "back to search" button, I found the page is directed to a url with "execution=e1s4" and the search result paging state is missed. I have thought I should be directed to original paging state. But that is not the case.
My question is whether a new execution key parameter means a new flow execution? If so, How can I confige to stick into a identical flow exection when I click "back to search" button. Because the "search-browse-back" operation should be regarded as a whole web flow execution, I found the practical run is different from what I thought it should be.
Thanks