# `window`

```strand
element window: surface
```

A window the compositor manages (`xdg_toplevel`): it tiles, floats,
moves, minimises and shows in task bars as an app's window does
(a settings window, a picker). The compositor decides its size: its
`width` and `height` (its content's while unset) are the size it asks
for, and its `min_*`/`max_*` the sizes it takes. Its compositor's
close writes its `open: <-> x` false. Its own `focused` is true while
the compositor has it focused, and `maximized`, `fullscreen`,
`tiled` and `decorated` follow the compositor (`id: w` and
`w.maximized`); `w.move()`, `w.resize(edge)`, `w.minimize()`,
`w.maximize()`, `w.fullscreen()` and `w.close()` ask it.
The compositor places, stacks and focuses it, so the `surface`
props that place a layer surface (`screens`, `layer`, `anchor`,
`keyboard`, `attach`, `scrim`, and `margin` on it) are load errors
(`check::window_prop`), and `screen` is not in scope in it. Escape
and focus loss leave it open; only the compositor's close and
`w.close()` write its `open` false.

It is a surface, written at the top level of a file.

Also every prop and event of [`surface`](/reference/elements/surface.html.md).

| Prop | Type | |
| --- | --- | --- |
| `title` | `text` | The title the compositor shows: `title: "Settings"`. Its name while unset. |
| `app_id` | `text` | The app id compositor rules match: `strand-<Name>` while unset. |
| `decorations` | `Decorations` | Who draws its title bar and borders: `server` (the default), the compositor where it offers to (`w.decorated`), or `none`, the config. |