What version are you running?
3.0.8
What's the URL of the page this enhancement relates to, if any?

Describe the enhancement and the motivation for it.
As code authors and code reviewers are going back and forth on a review, they're commenting on existing issues and having discussions about them. ReviewBoard is good about notifying me when new updates to a review have been made (a small indicator appears in the bottom right of my browser window and offers to let me reload the page so that updates will be loaded from the server), I have a hard time know which issues have been updated. I often have to resort to scrolling through the entire list looking for issues with thin blue vertical lines to alert me to a new reply or comment. What I would like, instead, is some of way to view all the most recently updated issues so that I can jump straight to them.
Unfortunately, due to technical issues beyond the scope of this feature request, we're not able to receive email messages from the ReviewBoard server. I expect that those messages would allow us to jump straight to the issues requiring our attention. So, in lieu of receiving email updates from the ReviewBoard server, it'd be a good update to have the ReviewBoard UI itself show me where I should direct my attention. This is especially true for large, complex code updates where reviewers and code authors are having to track 10's or 100's of issues across many diffs.
What operating system are you using? What browser?
macOS Mojave, Safari
Please provide any additional information below.