How to reveal hidden comments

I'm working on a document in Acrobat Reader (check for updates says I have the latest version), making comments for the document's creator. I can hide comments by pressing ctrl+shift+8, but I can't reveal the comments again by using the same shortcut. I can't find a manual option in the application or a solution online (other than ctrl+shift+8). How do I reveal comments that I've previously hidden? Thanks.