[BUG] Horizontal hover-over scroll bar prevents mouse access to expansion

[IanButterworth]

On MacOS, the hover-only horizontal scroll bar that appears for long messages makes expanding in-line results almost impossible.

One idea for a fix would be increasing the height of the in-line results so that the expand button has some space above the scroll bar.

There’s currently a few pixel high accessible clickbox on the expander when the scrollbar appears.

[IanButterworth]

Another solution.. don't show the scroll bar on hover, just on scroll
That's what the docs do. Note the first code block behavior in https://docs.julialang.org/en/v1/stdlib/Distributed/#Distributed.pmap

Or maybe just hide the scroll bar entirely?

[aviatesk]

I can repro this, let's just hide the scroll bar.
xref: JunoLab/atom-ink#279