Opening a message puts its subject in the browser-tab title. The title does
not stay in the tab strip: browsers keep it in history and in the
session-restore list, and screen shares show it. For mailboxes that hold
other people's correspondence that is a leak nobody audits.
A new feature gate, tabTitleSubjectEnabled ("Subject in Tab Title" under
Admin -> Policy), is on by default, so nothing changes for existing
installs. With it off, the title names the folder instead, so the tab still
says where you are. It is an admin gate rather than a user setting: whose
mail the boxes hold is a deployment decision.
The gate counts as off until the policy has loaded, so a subject never
slips into history while the setting is still unknown.
Refs #1159
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The tab title was "<context> - <app>", so two mailboxes open side by side
read the same in the tab strip and in the browser's session-restore list.
It is now "<context> - <account> - <app>", the order Gmail and Outlook Web
use: browsers cut a long title from the end, so the part that changes comes
first and the app name last. There is no setting for it; the account is what
tells the tabs apart.
The formatting, and the mail view's choice of context (composer, then
message, then mailbox), live in lib/tab-title.ts with tests. The mail view
sets its title through useDocumentTitle(), which other surfaces can use too.
Next renders the root layout's metadata <title> again on every client-side
navigation, after the surface has mounted; the hook puts its title back when
that happens. Only the surface that set the title last does so, so two
titles never fight.
Refs #1159
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Oğuz YılmazandClaude Opus 5.5