What version are you running?
4.0 alpha 0
What's the URL of the page containing the problem?
Review requests ie:

https://reviews.reviewboard.org/r/11308/
What steps will reproduce the problem?

Go to any review request page
There is a div with rb-c-button-group class that is anchored to the top of the screen (see screenshot 1)
The div contains two Publish Review buttons, I believe these two buttons belong to the Edit Review pop-up (see screenshot 2)

What is the expected output? What do you see instead?
The buttons should not be there
What operating system are you using? What browser?
Ubuntu 20.04, Chrome Version 86.0.4240.198 (Official Build) (64-bit)
Please provide any additional information below.