Strange little "Passwords..." popup

[etruscan]

I have this popup that sits right over the back button on my browser at most times. It can't be moved to the background. Clicking it or right clicking it does nothing. It doesn't even change the app focus. It cannot be moved. It will disappear only on a reboot, and then come back at some indeterminate time.

...so I don't know where this thing comes from and what application or part of the OS it's associated with. Any ideas?

 

[MightyGem]

It's usually comes up with known websites that require you to login. I normally get it as a dropdown from the login dialogue box, but occasionally it's in that position.

 

[MartyByrde]

Wonder if it happens with all browsers? I have not sen anything like that (I use Brave).