UnigramDev/Unigram/chat-preview-teardown • 9b344a2 • 4 files, +38/-7
Tear down the chat preview from the flyout's Closed event

ChatCell.ShowPreview hosts a second ChatView inside a MenuFlyout and hung its only
teardown on chatView.Unloaded, which never fires for a flyout-hosted view: the log
tail of the crash runs for another 109 seconds without the handler's "Unloaded"
line ever appearing. ChatView.OnCollectionChanged therefore stays subscribed to the
view model's Items after the flyout's XAML peers are gone, and the next collection
change reads Messages.ItemsPanelRoot through a separated RCW, throwing
InvalidComObjectException.

Teardown now hangs off the flyout's own Closed event, with Unloaded kept as a
secondary trigger, and ChatView.Deactivate ignores a second call so the order of
the two doesn't matter. The two forum topic cells already tore down from
flyout.Closing and so never had the hole; they move to Closed for a single pattern.

Reported by crash telemetry on 12.9.1.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

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