Make Unity Bar Sticky in Demo Page

[rajadain]

Overview

The Unity Bar should be "sticky" in the Demo page, i.e. it should not be affected by scrolling. It should always be visible at the top. As if it were absolutely positioned.

Is your feature request related to a problem? Please describe.

When testing the various Unity Bar options, one has to scroll down, which removes the Unity Bar from view. After changing the options, one has to scroll back up. This makes evaluating the effects of said options difficult.

Describe the solution you'd like

The Unity Bar should always be visible in the demo page.

Additional Context

This can either be done by custom styling the demo page, or adding a prop to the Unity Bar itself that does this. The latter would allow other client apps to achieve the same result, if the need should arise. But that is not a requirement of this issue. If the Demo page has it always visible, that is enough for this issue to be "done".