There seems to be a clash between TW and Codemirror – not sure how to dig out the source of the CSS.
Note, two vertical scrollbars…
Form the image you can imagine how uncomfortable that is to use – the scrolling behaviour does not sync with cursor movement at all. Mousewheel seems fine.
In the devtools inspector…
the highlighted line is the issue. Digging deeper…
Obviously, I can override that overflow:auto
– when I do, the outer/erroneous scrollbar disappears.