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Classroom_Desktop/docs/browser.md
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ekklesiaandClaude Opus 5 0e91b4cbd3 fix: keep the dock's Close button reachable
The Close button followed focus, and moving the pointer down to the dock
moves focus off the popup. So the button disappeared somewhere on the
journey to it, and a secondary Chrome window could not be closed with a
mouse at all. Found on the endpoint; my fault.

The target is remembered instead. Once a secondary window has been
focused the dock keeps offering to close it, and losing focus — to the
dock, the main browser, a print dialog, any layer-shell surface —
changes nothing. It moves on only when that window closes or another
secondary takes over, and it falls back to another open secondary rather
than to nothing, so cancelling a print dialog leaves the render window
still closeable. It is chosen from the secondary list, which never
contains the first window, so it can never name the main browser.

Restoring the floating role to a window that already existed no longer
moves or focuses it. Moving it would undo wherever the teacher dragged
it; focusing it would raise the render window over the print dialog
sitting above it, which is one way the print flow was getting disturbed.

Verified by driving a real pointer through the exact path that was
broken: pointer over the popup, click to focus, then travel down to the
dock in steps, screenshotting throughout. The button is still there on
arrival, at 992,1041. Then the print flow: main browser, render window
and a separate Print dialog, pointer to the dock, button still there,
and killing the dialog leaves the render window as the new target with
the main browser untouched.

The button's own action could not be actuated in that harness, because
synthetic pointer input does not reach Wayland clients under headless
sway — the Browser button does not respond to it either. The action was
run directly instead, closing exactly the remembered container and
leaving main Chrome alive.

Co-Authored-By: Claude Opus 5 <[email protected]>
2026-09-07 20:05:42 -05:00

8.6 KiB
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The classroom browser

A classroom computer is a shared appliance, not somebody's laptop. There is one local Chrome profile, owned by the room. Teachers sign into websites; nobody signs into Chrome.

Policies

All of these are in /etc/opt/chrome/policies/managed/ekklesia-classroom.json, and every name was checked against the strings of the installed Chrome 152 binary with deliberately invalid names as a control.

Policy Value Why
BrowserSignin 0 Chrome never asks who is using it
SyncDisabled true Explicit, though BrowserSignin: 0 implies it
SigninInterceptionEnabled false No "this account is managed" bubble
BrowserAddPersonEnabled false No new Chrome profiles
BrowserGuestModeEnabled false Removes the Guest entry point from the profile menu
ProfilePickerOnStartupAvailability 1 No profile picker at startup
PasswordManagerEnabled false No offers to save passwords
PasswordLeakDetectionEnabled false No leak warnings
BackgroundModeEnabled false Closing the last window really ends the session
CookiesSessionOnlyForUrls ["[*.]wonderink.org"] Wonder Ink should not outlive a teacher
DefaultBrowserSettingEnabled false No default-browser prompt
PromotionalTabsEnabled false No welcome tabs
MetricsReportingEnabled false —
ShowHomeButton true One obvious way back
HomepageLocation Wonder Ink —
HomepageIsNewTabPage false —

BrowserGuestModeEnabled: false is the answer to "other profile switching entry points". Guest mode is the one that survives BrowserAddPersonEnabled: false, and disabling it is the supported mechanism — no UI hacks. Guest mode is not used as the browsing model: the room needs one persistent profile so the church YouTube login survives.

None of this touches website logins. Wonder Ink, Google and YouTube sign-ins are ordinary site sessions and are unaffected by BrowserSignin: 0, which governs signing in to the browser.

Secondary Chrome windows

Chrome gives the main browser and additional top-level windows the same google-chrome app ID, the same browser PID, and no reliable distinguishing properties. Page titles are site content and are deliberately not used.

classroom-chrome-windows follows the Sway tree during the session and assigns roles by creation order:

  • the first Chrome top-level is the main classroom browser and remains tiled, maximised and borderless;
  • every later Chrome top-level floats at 76% of the logical workspace, centred above the main browser;
  • a red Close × button is placed at its top-right and kills only that secondary container;
  • when the secondary closes, the still-tiled main browser underneath has not been moved or resized.

The Sway for_window rule still only removes Chrome borders. There is no broad Chrome floating rule: the session helper issues commands against the exact con_id of each additional container. If the main window is closed first, the oldest remaining Chrome window is promoted back to the tiled, borderless main role.

What the policies do not remove

The avatar button stays in the toolbar. Verified by screenshotting Chrome with these policies applied and comparing against Chrome without them: the button is in the same place either way.

What changes is what is behind it. Sign-in, adding a profile and Guest mode are all disabled by policy, so the menu has nothing left that creates or switches a profile. Chrome 152 has no policy that removes the button itself — ProfileSwitcherEnabled and similar names do not exist, checked against the binary — and hiding it would mean the UI hacks this is meant to avoid.

Worth a look at the endpoint: open that menu once and confirm it offers nothing actionable.

Wonder Ink between teachers — CONFIRMED WORKING

Teacher A signs in, uses the room, Chrome closes, teacher B opens Chrome and Wonder Ink is signed out, while YouTube stays signed into the church account.

CookiesSessionOnlyForUrls with [*.]wonderink.org does it. That pattern covers app.wonderink.org and every other subdomain.

Confirmed on the physical endpoint, which is the only place it could be: it needs a real Wonder Ink login. It could not be established here, and three attempts to prove the mechanism against a local test site were inconclusive because the positive control never worked — so this was shipped as unverified and the endpoint settled it.

Two consequences worth keeping in mind.

Wonder Ink's session is therefore in cookies, not in localStorage. That matters because there is no per-site Chrome policy that clears localStorage on exit: ClearBrowsingDataOnExitList and BrowsingDataLifetime both exist in Chrome 152 but are global, and blanket clearing would take YouTube with it. Had it gone the other way, this would have needed a classroom-owned cleanup instead.

If Wonder Ink login is "Sign in with Google"

app.wonderink.org loads Google Identity Services (accounts.google.com/gsi/client), so Google sign-in is at least offered.

If teachers sign into Wonder Ink through Google, clearing wonderink.org will sign them out of Wonder Ink — but the Google session at accounts.google.com is deliberately kept, because that is what keeps YouTube Premium signed in. The next teacher could then be one click from re-entering the previous teacher's Wonder Ink account.

These two requirements genuinely conflict, and which one applies depends on how teachers actually sign in. Worth knowing before Sunday. If teachers use Wonder Ink email-and-password accounts, there is no conflict at all.

Extra browser windows

The first Chrome top-level window is the classroom browser: tiled, borderless, filling the desktop above the dock. Every later Chrome top-level floats instead — centred, about three quarters of the output, borderless — so it sits over the browser rather than tiling beside it and shoving the lesson to half width.

Which window is which can only be creation order. Verified on a real session: every Chrome top-level has the same app_id, the same shell=xdg_shell, the same PID, a null transient_for, and sway exposes no window_properties, window_role or window_type for Wayland toplevels at all. Page titles are deliberately not used.

classroom-chrome-windows follows sway's own window events rather than polling, so dragging a popup costs nothing.

Closing one

The Close button is in the dock, and it is sticky. Once a secondary window has been focused, the dock keeps offering to close it until that window goes away.

That stickiness is the whole design. It first followed focus, which made the button impossible to click: moving the pointer down to the dock moves focus off the popup, so the button vanished somewhere on the way to it. Nobody could ever reach it.

The remembered target changes only when:

  • the window it names closes — and it then falls back to another secondary that is still open, so cancelling a print dialog leaves the render window still closeable; or
  • another secondary window is focused and takes over.

Focus moving to the dock, the main browser, a print dialog or any layer-shell surface changes nothing. The target can never be the main browser: it is chosen from the secondary list, which never contains the first window.

Clicking it runs [con_id=N] kill on that exact container: never the main browser, never a Chrome process.

An earlier attempt anchored a close button to the popup's own corner as a separate layer-shell surface. On real hardware it chased the window and flickered, because every position change meant tearing a surface down and building another. The dock does not move, so it cannot chase anything.

Note that a stock sway title bar has no close button, so putting the border back would not have solved closing either.

Printing

A site's own Print button opens a Chrome window to render the document and then a print dialog on top of it. Verified in a real session: that is three top-level windows — the browser, the render window, and a separate "Print" dialog — and the render window is indistinguishable from a genuine popup by anything except its title.

No special case was added, because there is no signal to special-case on. The generic treatment already produces the right result: the render window and the print dialog both float centred and borderless over an untouched main browser, the dialog is the obvious foreground window, and anything left behind is one dock click away. The render window used to be the one thing on screen wearing a sway title bar; it no longer is.