I had trouble with keyboard shortcuts. It turns out Ghostery is blocking them, probably because the scripts are loaded from another domain which Ghostery or ad-blocking lists block.
By disabling Ghostery for trello.com I was able to regain use of keyboard shortcuts. This problem and fix likely apply to other Confluence products as well.
I'll file an issue with Ghostery, but it may be an issue with the blocklists they use (or an issue with Confluence loading user-useful scripts from the same domain as tracking or ad scripts).
Unknown if related: