---
name: Pane
slug: pane
category: layout
status: published
created: 2026-08-21T00:00:00.000Z
modified: 2026-08-21T00:00:00.000Z
definition: A layout container that holds one destination's content inside a
  window, either fixed or flexible in width, combined with other panes to fill
  the space.
aliases:
  - name: fixed pane
    source: material
  - name: flexible pane
    source: material
  - name: floating pane
    source: material
  - name: semi permanent pane
    source: material
tags:
  - windowing
relations:
  contrastWith:
    - supporting-pane
  variantOf: []
  partOf: []
  seeAlso:
    - split-view
    - inspector
implementations:
  - system: material
    name: Panes
    url: https://m3.material.io/foundations/layout/scaffold/overview
sources:
  - title: Scaffold, Material Design 3
    url: https://m3.material.io/foundations/layout/scaffold/overview
demo: inline
exhibit: false
useWhen: naming one region of a multi region window
---

A window with more than one thing in it is divided into panes, and the pane is the unit that
division is counted in. A mail client is three panes: mailboxes, messages, and the message you
are reading. A settings window is two. The word is useful precisely because it names a region
without naming its contents: you can say "the middle pane" to someone who has never seen your
app and be understood, which is why every toolkit that lays out windows ends up with panes in
its vocabulary. Material's [scaffold](/scaffold) documentation is one of the tidier statements
of the idea, and it is where the kinds of pane get their names.

Those kinds are about width, and about who decides it. A fixed pane states its own width and
keeps it, so the pane beside it absorbs every change in the window. A flexible pane is the
opposite arrangement seen from the other side: it takes whatever is left over, which means its
neighbour is the one holding a number. A floating pane comes off the surface entirely and sits
over the content with an inset and an elevation, so what is underneath keeps its full width. A
semi permanent pane is one the reader can send away and call back, occupying real space while
it is there rather than hovering over the content like a drawer. Most windows mix them: a rail
that never moves, a list that keeps a set width, and a reading pane that takes the rest.

Pane is not the same word as panel, though systems use panel loosely for any boxed region,
including cards and popovers, which are not panes at all. A pane is a division of a window's
own space and it is always adjacent to its siblings rather than floating in front of them,
which is why an [inspector](/inspector) is a pane and a popover is not. The related words
divide up differently: [split view](/split-view) names the arrangement of two panes and the
draggable boundary between them, [list detail](/list-detail) names the specific pairing where
one pane indexes what the other displays, [supporting pane](/supporting-pane) names the
secondary region that assists the main one, and [sidebar](/sidebar) names a pane by its
position and its usual job. A [canonical layout](/canonical-layout) is a named pane
arrangement worth reusing.

The pane is also where responsive layout actually happens, since a window narrowing does not
change what the panes contain, only how many of them fit. The usual sequence is that a three
pane window becomes two panes and then one, with the pane that lost its place turning into a
route you navigate to, or a drawer you summon. Deciding that sequence in terms of panes rather
than pixels is what keeps a large layout describable: three panes, one of them fixed, the last
one collapsing first.