Mosaic:

- Scrolls to random place way down in page when cell is executed or split
- drops cell at bottom when dragging over empty space in group (cell not fully expanded)
- expands cell in row way too tall after dragging out from column in row
- group padding doesn't seem to register for dragging over / dropping on (try to add cell in line with column in row)


Jupyter:

- large image output de-renders when top is out of scroll range. Need to enable output scrolling then disable to get size to update.
- scroll to next thing is jumpy (CSS: scroll-behavior: smooth should fix)