Windows Tray app crash-loops with Microsoft.UI.Xaml.LayoutCycleException under rapid event throughput

Environment

OpenClaw Windows Tray version: 2026.7.1 (also reproduced on 2026.7.1-2)
OS: Windows 10.0.29648.0, x64
Gateway version: 2026.7.1 (remote gateway over wss://)
Topology: Remote gateway, node mode enabled
Summary
The Windows tray app repeatedly crashes and auto-restarts under load, with the following unhandled exception in crash.log:

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Microsoft.UI.Xaml.LayoutCycleException: The text associated with this error code could not be found.
Element is already the child of another element.
Observed pattern
Over a ~30 minute window, the tray app restarted at least 6 times:

21:05:41, 21:08:54, 21:12:30, 21:25:43 (local +02:00), plus the crash itself at 21:21:02
Restart intervals as short as ~3 minutes apart during the worst period
Suspected trigger
Tray log (openclaw-tray.log) shows very high-frequency inbound events during active sessions — presence, health, node.invoke.request/result, chat, sessions.changed, agent stream events — sometimes multiple events within the same millisecond. These appear to feed directly into UI-bound collections (activity stream, node list, session list). Under sustained high throughput, this likely races the WinUI layout/measure-arrange pass, causing an element to be re-parented while still attached elsewhere — the classic root cause of LayoutCycleException.

Impact

Tray app becomes unusable during high-activity sessions (agent actively running tool calls/exec approvals)
Requires manual force-kill + relaunch to recover
No user-facing error dialog observed — app just disappears/restarts silently
Suggested fixes

Batch/throttle UI updates from the event stream (e.g. coalesce rapid presence/health ticks before dispatching to UI thread)
Ensure all collection mutations happen on the UI thread via DispatcherQueue, not directly from the websocket receive callback
Add global unhandled-exception handling around the XAML layout pass to prevent full app termination (log + recover instead of crash)
Attached crash.log tail:

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[2026-08-30 21:21:02.506] UnhandledException
Microsoft.UI.Xaml.LayoutCycleException: The text associated with this error code could not be found.
Element is already the child of another element.

Start with crash.log and openclaw-tray.log, then trace the high-frequency presence, health, node, chat, session, and agent-stream events into the tray's UI-bound collections. Determine whether collection mutations or element ownership occur during concurrent updates, and validate the fix by reproducing sustained event throughput without further LayoutCycleException crashes or restarts.