[Windows] Codex desktop main process crashes after in-app Browser Use tab teardown (external reports, native cause unknown)

Finding: Multiple external reporters on Windows say the Codex desktop main process exits shortly after an in-app Browser (IAB) Browser Use tab is torn down, on builds up to MSIX 26.1007.2314.0. Native cause is unknown, and KFA did not reproduce this; everything below is external-report evidence. Symptom: The whole app disappears, interrupting tasks, and relaunches normally. Commenters retain only a Crashpad sidecar with capture_kind=crash, ptype=browser, x86_64, written about 0.4-1 s after the last desktop log lines. Logs typically show debugger listener unregistered (reason=target-close), webview disposal, guest teardown, sidebar page closed, and often a Browser Use PiP metadata entry ([comment](https://github.com/openai/codex/issues/43347#issuecomment-5977328190), [comment](https://github.com/openai/codex/issues/43347#issuecomment-6100296979)). Versions: The original report cited 26.901.5280/6511 ([issue](https://github.com/openai/codex/issues/43347)). Later comments report 26.908, 26.915, 26.917, 26.924, 26.930, 26.1002.7124.0 and 26.1007.2314.0, including two crashes on 2026-10-10 after a Store update ([comment](https://github.com/openai/codex/issues/43347#issuecomment-6100296979)). One report on 26.820.9563.0 shows it predates 26.901 ([comment](https://github.com/openai/codex/issues/43347#issuecomment-5624763191)). A Windows 10 report exists ([comment](https://github.com/openai/codex/issues/43347#issuecomment-5975345681)). Scope: The title says last tab, but later reports show crashes when other Browser Use tabs remained (e.g. appBrowserUseTabCount=1 or 2) ([comment](https://github.com/openai/codex/issues/43347#issuecomment-6098036280), [comment](https://github.com/openai/codex/issues/43347#issuecomment-6100296979)). Closure is often an agent tab.close() call, but one reporter saw no explicit close before an end-of-turn cleanup crash. It is intermittent; many closures succeed. Checks: Reporters found no matching Windows Application Error, resource-exhaustion or display-reset events, which does not exclude other native causes. ResizeObserver errors and tabID=undefined PiP entries are noted but not established as causes; one reporter found most undefined-tabID entries did not precede a crash. Cause/fix status: No native dump or stack exists, so cause is unconfirmed; a teardown race is a reporter hypothesis. No maintainer response, fix commit or released fix appears in the supplied sources, and a newer package was reported still affected. Workaround (unverified): Reporters avoid discretionary IAB tab.close(), reuse tabs, keep result tabs open, or use an external browser. They state this is not a verified fix, and the external-browser option was untested ([comment](https://github.com/openai/codex/issues/43347#issuecomment-6098036280)).