It looked <main> up when it bound, which the lazy pages won. On a first
visit to the channel page or Plex the chunk is still loading, so the
Suspense fallback is on screen, there is no <main> to find, and the effect
gave up — its dep never changes again, so the button stayed dead for that
whole visit and only worked once the chunk was cached.
It now reads the scroller off the scroll event instead, captured on the
document: scroll doesn't bubble but it does capture, so there is nothing
to look up and nothing to race. Also 50% bigger, as asked (44 -> 64).
peter
26c7ed7471