The original approach to the RB.PageView sizing logic was based in

part on how the datagrid pages behaved before. However, the logic was

not quite right. It made some bad assumptions on sidebar offsets

(resulting in the sidebar being just a bit too far down the page) and

its approach to calculating the bottom padding of the page both wasn't

necessary and got in the way of upcoming unit tests.
This redoes the logic entirely to be more clear in what it calculates

and how, to throw away all the bottom calculation stuff (in favor of

using jQuery's outerHeight()), and to then remove all the calculated

heights passed to onResize() (which are now less useful, and might as

well be calculated by the caller). It also properly restores heights

when going in/out of mobile mode.
While here, I also found that the drawer functionality had regressed

toward the end of my work, and that sidebar pointer events were being

blocked. This was due to the lack of a pointer-events: none when

hidden. That's been added, with pointer events restored when shown.

Carefully inspected the heights and padding on the sidebar and page

container in both desktop and mobile modes, when initially shown,

on resize, when toggling modes, and when the drawer's opened in

mobile mode. Made sure everything was exactly on screen and lined

up with edges.