I think the simplest fix for this is to add the col on the right to just the "Comments" tab, and make the files changes and commits tabs full width.

Here is a screencast of what i had in mind:

Filed a PR#1536 containing the change demonstrated above.

That would be fine for me, I dunno if people with wider screens might be sad to lose the sidebar. But then, sometimes people write pretty wide code.

Let's close this as fixed for now and we can reconsider if needed when #1536 will have been pushed to prod.

Thanks for the report, the discussion and the fix everyone :)