Watching Tags

How… exactly do I go putting a tag into my watchlist nowadays? I don’t see the option when searching for it, the + on each that has disappeared, and in general, there doesn’t seem to be any way to do it.
 
So what gives?

Go to settings and enter manually, I suppose.

@Solitude  
But that’s a terrible solution…

@Background Pony  
Also the only one, far as I know.