I have absolutely no idea what to call it, but when I used to approach items, a small pop-up would apear with the name of the object that I would activate were I to press 'e' at that exact moment. It would also tell me whether or not taking said object would be theft. It would also give me the names of all characters without having to actually start a conversation with them.

This pop-up is now missing. I have no idea how, but it is. I've tried fiddling with the settings, but to no avail.

Can anyone help me? This is really quite the pain.

Have you downloaded any mods recently?

No, I haven't. Not one.