An extension's page can send its tab to a website

1Password's Sign in did nothing (reported on X). With its Mac app not
connected, the button sets location.href to its sign-in page on
start.1password.com - but the tab's view was built from the extension's
configuration, which WebKit keeps to that extension's own pages, so the
load went nowhere, without an error. Now a main-frame move from an
extension's page to http(s) is caught before it's lost, and the tab is
swapped where it stands for an ordinary one on the address: to the eye,
the page went there. Extensions follow the swap as a closed and an
opened tab, as they would any other.

Found with a new test-only bench verb, `tap ID SELECTOR` (or
`text=Words`): a real mouse click delivered to the view, trusted as a
hand's is, since a password manager rightly ignores element.click().
Checked in a probe under its own bundle id with 1Password 8.12.37 from
the Web Store: Sign in now lands on my.1password.com/signin in the same
tab. Bitwarden 2026.8.0 works up to its sign-in screen (popup, its 7.5
MB WebAssembly, its worker); blank-after-sign-in needs an account.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>