So I figured out that with text-only messages (not pictures or links) the only way to get the context menu to come up is to right click right at the very leftmost side of the message. There's a few pixels there that let you interact with the message. Is this just me? I searched the forum and didn't see anything. Is there a setting I can modify? Messages on El Capitan was garbage, but at least I could right click on non-image messages to send a quick thumbs-up.
(Side note, it's very difficult to talk about 'text messages', because I don't mean SMS messages from non-Apple devices, I mean Messages that are text, which is why I've described them as 'non-image messages' as an unsatisfying workaround.)
(Side note, it's very difficult to talk about 'text messages', because I don't mean SMS messages from non-Apple devices, I mean Messages that are text, which is why I've described them as 'non-image messages' as an unsatisfying workaround.)