So I needed to add a user to a database but when I go to Home>Privileges and click on “edit privileges” on any user, same page opens up in a frame (or same page in different tab when middle-clicked).
https://i.stack.imgur.com/6xQtN.png
edit:
solved it by reinstalling phpMyAdmin.
phpMyAdmin is totally awesome but it does have a fair number of browser quirks related (I believe) to cookies. When I start seeing odd behavior like that, I try a different browser. If it works in the other browser, just do your work there for the time being or else restart your current browser (or delete the relevant cookies from your current browser).
That’s not so much an answer as a workaround, but it ought to get the job done.