The measure-once design missed a host restyled from sized to height:auto after mount WITH in-flow content: it
stayed sized at its content height instead of getting the floor back, as the old probe did.
- After mount, follow() re-probes only when the reading says the host may have changed kind: floor on and the
host shorter than the floor (styled after mount, or capped), or floor off and the host changed size (it may now
follow its content). The re-probe saves every scrolled descendant (through shadow roots) and puts it back
before the frame paints, so no reader state is lost. A window-height change on a content-sized host still
writes nothing.
- A host capped below the floor (max-height) is latched by the probe that finds it, until it reaches the floor
again, so it is never re-probed in a loop. The 1 s post-flip window is gone.
- check:host-floor gains arm H (sized → auto with 420 px of content: the floor returns, at most one flip, the
scrolled child keeps its scrollTop) and counts re-probes in D/E. Poisons: the old per-resize probe, no capped
latch, no re-check of a sized host, no scroll restore.
- library/elements/hostFloor.js holds the decision ProfileLoader uses: probeOnce() at mount, follow() on every
host resize (reads only; at most one flip of the floor).
- A host CAPPED below the floor (max-height) follows its content up to the cap. It is found at mount, or, if
the cap arrives later, by the host shrinking right after a flip; either way it is latched as content-sized
and never flipped again, so it cannot loop. The post-flip check runs before the collapse rule, so a capped
host with empty content is latched rather than flipped back and forth.
- check:host-floor (gates:pre; self-test in gates:post): a stub DOM with a scrolled child that clamps when the
loader collapses. After mount, host resizes never write the loader nor move the child; a sized host fills;
late sizing flips once; a max-height cap (at mount: 0 flips; after mount: at most one flip and one revert)
never loops; a collapsed host gets the floor back; an inline host is left alone. Poisons: the old per-resize
probe, and a missing latch.
