I had a problem when dealing with back button.
In fact at this line: https://github.com/jquery/jquery-mobile/blob/master/js/jquery.mobile.page.sections.js#L59
$this should be $page.
Thanks for ghislain to have worked with me on this problem.
I talked with @johnbender who seems to agree with the fact that $this should be $page.
The back button logic needs to be evaluated during pageshow, not pagecreate. If you load page A navigate to page B, then return to page A, the back button will not show up! If you load page B first, then navigate to page A, the back button will show up! This also means that if you reset the urlHistory stack and then load the page, the back button could still show up!