Header bounces/jumps during transition when scrolling very slowly

[dflitner]

Here is a video showing the issue (Slack).

When you first scroll down the screen, there's an issue where the header hides/shows the universal menu and it flashes back and forth and jumps the rest of the header up and down due to the transition.

I reported this to the Unity team so hopefully they have a ticket open.

[dflitner]

This is "fixed" for admin users due to a class not being applied for admins (fixed header conflicts with admin_toolbar). We should expand this to all roles/permission who can edit/use the toolbar.