Real error from the field: navigating to the party page threw inside
Emby's own viewmanager.js (v4.10.0.40): TypeError, cannot read
properties of undefined (reading lifeCycleAbortSignal), at
getResumeOptions/dispatchViewBeforeShow. EnableInMainMenu=true was
never confirmed by any real example (only EnableInUserMenu=true was,
via the forum thread cited in Plugin.cs) - it very likely routes the
page through the newer ViewManager meant for full content views
(Home, Movies, ...), which expects a lifecycle contract this static
embedded-resource page doesn't provide. Reverting to exactly the
confirmed-working combination.
The raw page itself was confirmed served correctly beforehand (200,
correct content, via GET /web/configurationpage?name=WatchPartyRoom)
so the plugin/registration side was never the problem - just this one
flag.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>