When we upgraded from 2.11 to 2.12, stash stopped remembering that I like to view diffs in side-by-side mode. Now every time I visit a pull request I have to type "shift D" to switch to side-by-side mode. Not a huge deal, but enough of an annoyance that I'd like to see it fixed.

To reproduce:

1. View a PR in side-by-side diff mode.
2. Copy URL, paste into a new tab.
3. PR is show back in normal diff mode.