Layout issues in "Show changes since last view" view #2296

With RGH:

Without:

Issues (highlighted boxes above):

1. the Files header has broken to two lines
2. the first file's header has broken to three lines

Repro

I think that this only happens when you've selected "Show changes since your last review"

and mayyybe when the top file in that view is showing "Changed since last view".

I can't get it to happen when I've selected all commits, individual commits, nor commit ranges within the PR.

Speculating on causes

I'm a bit mystified as to issue 2 above, but issue 1 seems caused by RGH adding these two buttons which probably don't have room when "Clear filters" is visible as it is when you have selected "Show changes since your last review".