Problem

Inside a boosted shell (hx-boost + hx-target="#main" + hx-select="#page-content"), a local-swap form/fragment inherits hx-select="#page-content". Its own fragment response has no #page-content, so htmx selects nothing and swaps EMPTY — the element vanishes. app.check()'s htmx rule does warn (great), but it recommends hx-disinherit, which is the wrong lever: hx-disinherit controls what an element's descendants inherit, not what the element itself inherits. Adding it did nothing.

How it hurt (Lucky Cat #220)

The convert form silently vanished on submit. hx-disinherit="*" (per the warning) didn't fix it. The actual fix was overriding hx-select on the form (hx-select="#convert-form"). I nearly hit the same on the chart timeframe toggles.

Suggested fix

Correct the warning text + docs: for an element doing its own swap inside the boosted shell, override hx-select (and hx-target/hx-swap) on the element itself. Mention hx-disinherit only for the descendant case.