Commenting functionality in "Viewing changes" mode

[patrickmorgan08]

Having the "Viewing changes" mode is really helpful for reviewers. They can easily identify, and then jump directly to, the updated content in each file so they don't have to review the whole document each time.

However, the Comments features don't work when in that mode. Thus, reviewers can't drop comments on the affected sections without jumping back to the editor view. Would be smoother to enable comments in this mode.