Mitigating browser scrolling jitters when multiple column layouts scroll at distinct paces concurrently.
If you stream 3 models side-by-side, each column scrolls downward as new tokens are prepended or appended. Stacking standard elements with `scrollTop = scrollHeight` resets the viewport continuously, resulting in severe user scroll-jerk.
We bypass this by setting `overflow-anchor: auto` explicitly on our flex column lanes. This tells Chromium to lock the viewport relative to the visible content block rather than top nodes, allowing users to scroll up to review historical outputs in one model, while companion models continue streaming out of sight without pulling their page frame.