demo · v139
Anchor Fix
v139 prefers earlier in-viewport candidates when picking the scroll anchor. Scroll either column to the middle, then click "inject above" — watch the v139 column hold its visible content while the old behaviour jumps.
Scroll a column to position 4-6, then click "Inject above".
v139 (scroll anchoring on)
pre-v139 (anchoring off, simulated)
the css
/* No new CSS. v139 improves the anchor-candidate
picking algorithm: earlier in-viewport elements
win over later ones, so upstream DOM insertions
cause less visual shift. */
.feed { overflow-anchor: auto; } /* default */