I didn't see this issue anywhere so if it IS elsewhere I apologize.

I get a persistent long and narrow blank popup that will not stay gone. It does not matter what web page I am on and it even appears on the downloads and settings tabs when I open them.

I am using the Mac version 18 and I've used Adblock and run a malware check using Sophos anti-virus.

You can see it across the bottom of this screen-shot.

https://app.box.com/s/y5hg753cidarf4sk2cui

Any ideas to make it go away?