Desktop is a HashRouter over one file:// document, so every route is a
distinct URL to Chromium's per-URL zoom store. A route the user never
zoomed on has no record at all and resolves to the host default (100%) —
that is every fresh session and every never-visited settings tab.
In-page navigation fires neither did-finish-load nor any window event,
so nothing re-asserted the persisted level. The window dropped to 100%
while the Appearance control kept reading the chosen scale, because the
renderer only learns of zoom changes through 'hermes:zoom:changed',
which never fired. Touching the setting sent a fresh apply, which is
why it appeared to fix itself.
Re-assert the persisted level on main-frame did-navigate-in-page.
Verified on real Electron 40.10.2 / Chromium 144 (win32): a recordless
hash route reports 100% at the event, so the existing drift-guard sees
the drop and re-applies, and still no-ops when the route's record
already matches.
Fixes#48658Fixes#38854Fixes#79863
Co-authored-by: Brooklyn Nicholson <brooklyn.bb.nicholson@gmail.com>
Clark Vines
b637ee0fc6