feedBack/docs/plugin-panes.md

Detachable panes (window.feedBack.panes)

Pop a panel out of the app into its own OS window, and leave it there: while you play, across song switches, on a second monitor, minimized to the system tray.

Panes exist because the player's rail popovers are exclusive — opening one closes the last. You cannot watch the mixer while riding the camera, and both vanish the moment you want to look at the highway.

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The whole idea, in one sentence

We move the real element.

Not a copy of your panel. Not a re-implementation of it in the pop-out window. The actual DOM node. Same-origin windows can adopt each other's nodes, and an adopted node keeps its event listeners and its closures — so your panel goes on running your code, against your state, in your realm. The app's stylesheets are copied into the pane window, so it looks identical too.

What you popped out is what you get. That is the promise, and it is the reason there is no ctx, no state mirroring, no cross-window RPC and no second copy of your UI to keep in step with the first. Those are all solutions to a problem we simply do not have.

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Adding a pane to your plugin

Two lines.

// Guard: the panes API is optional. On a host without it, skip both calls and
// your panel behaves exactly as it does today.
const panes = window.feedBack && window.feedBack.panes;
if (panes && typeof panes.register === 'function') {
    panes.register({
        id: 'camera_director',
        title: 'Camera Director',
        icon: '🎥',
        element: () => panelEl,      // your existing panel, as it is
    });
    panes.attachChip(panelEl, 'camera_director');
}

attachChip() injects the standard pop-out chip (⇱) — same glyph, same place, same behaviour in every plugin. Clicking it moves your panel to whichever host the router picks — usually a pop-out window, but the dock when a window can't be had (a blocked pop-up, or defaultHost: 'dock') — and leaves a "⇲ … is popped out" stub in its place. Clicking the stub brings the panel back, to exactly the spot it left. Core owns the chip, the hiding and the stub, so you write no show/hide logic.

That's it. Your sliders, your presets, your tabs, your CSS, your event handlers, your state — all of it comes along, because none of it moved anywhere except into a different window's document.

element is a function for a reason

It is resolved at open time, not at registration. Plugins commonly build their panel lazily on first use, or rebuild it wholesale when something changes (Camera Director rebuilds its panel on every mode change). Asking for it when we need it means we always move the live one.

If you rebuild your panel, re-attach the chip. Rebuilding takes the chip with it. attachChip() returns a detach(); call it before re-attaching, and again in your teardown — otherwise you leave a stub pointing at DOM that no longer exists.

if (chipDetach) chipDetach();
chipDetach = panes.attachChip(panel, PANE_ID, { header: toolsEl });

Re-attaching is safe while the pane is popped out: the chip reconciles against the pane's real state, so a panel rebuilt mid-pop-out stays correctly stubbed.

The two things core changes about your element

1. Placement. .fb-paned is added while the pane is out:

position: static; inset: auto; margin: 0; width: 100%;
max-width: none; max-height: none; z-index: auto; box-shadow: none;

Your panel was almost certainly a fixed overlay pinned to a corner of the app (position:fixed; top:72px; right:18px; width:288px). Alone in its own window, every one of those is wrong — it would float 72px down from the top of a 380px window, still 288px wide, still casting a shadow over nothing.

Note there is deliberately no display override: a panel that is display:flex or grid stays that way. Colours, borders, radius, padding, fonts and your panel's own internal layout are untouched.

2. Visibility. A panel is usually hidden until its launcher is clicked, and a pane can be opened from the tray or the rail without that ever happening — so core un-hides it, in the two ways a panel is actually hidden:

el.hidden = false;
if (el.style.display === 'none') el.style.display = '';

Both are restored exactly as they were when the pane docks, along with the .fb-paned class. A panel that was closed when you opened its pane from the tray goes back to being closed; one that was open stays open.

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Spec

feedBack.panes.register({
    id,                    // required, unique
    element,               // required — an Element, or a function returning one
    title,                 // shown in the pane window's title bar, the dock card, the tray
    icon,                  // one glyph, for the dock/tray/launcher lists
    width, height,         // the pane window's initial size (it remembers yours after that)
    defaultHost,           // 'window' (default) or 'dock'
    onHost,                // optional (hostId | null, el) => void — re-measure/re-anchor
});

feedBack.panes.attachChip(el, paneId, { header })   // → detach()
feedBack.panes.open(id, { host }) / close(id) / detach(id) / dock(id) / focus(id)
feedBack.panes.isOpen(id) / hostOf(id) / get(id) / list()

attachChip puts the chip in the header element you pass, else in el.querySelector('[data-pane-header]') if it finds one, else at the top of el. An explicit header always wins.

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Hosts

detach(id) puts a pane in the best host available:

host
window	10	A real OS window. In the desktop app: remembered bounds, always-on-top, system tray.
dock	0	A card in the in-window stack. The floor — always available, so opening a pane can never fail.

You don't pick; you declare defaultHost and the router does the rest.

In the desktop app a pane you left popped out comes back popped out on next launch. In a browser it comes back docked — a browser blocks window.open() without a user gesture, so restoring it would only ever produce a "pop-up blocked" toast. The chip pops it out again on your next click.

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Things worth knowing

1. Your code still runs in the main window. The element is displayed in the pane window, but its closures, its timers and its document references all still belong to the main realm. That is exactly why everything keeps working — but it means a document.body.appendChild() inside your panel (a tooltip, a popover) lands in the main window, not the pane. Anchor such things to the panel itself, not to document.body.

2. Chromium throttles a backgrounded window's requestAnimationFrame. While the user is looking at your pane, the main window may be in the background — and your rAF lives there. Event-driven panels (sliders, buttons, presets) are unaffected. A panel that animates continuously may run slowly while it's the only thing you're looking at.

3. The element goes home exactly where it came from — same parent, same position among its siblings. Don't move it yourself while it's popped out.

4. A pane the user closed with the window's X button is reaped (a crashed renderer never gets to say goodbye), and your element is docked back. Without that, your panel would be stranded in a dead document with no way back.

5. Nothing here is required. On a host without the panes API, feedBack.panes is undefined, you skip both calls, and your panel behaves exactly as it does today.