# Resizable panels

A React component in [Beamline](https://beamline.io/)'s [Layout](https://beamline.io/components/layout) category. Live demo: https://beamline.io/components/resizable-panels

Panes that trade space across draggable dividers; each divider is a focusable separator with arrow keys, limits, folding for collapsible panes and double-click to restore.

## Use it for

- Split views people resize: mail, editor and preview, list and detail.

## Not for

- Fixed layouts whose sizes never change (CSS grid).

## Anatomy

- root (unpainted; the caller's one m-surface frame holds the split)
- pane (unpainted, scrolls its own content)
- divider (1px line-soft seam, 13px hit area)
- grip (visible at rest; accent on hover, drag and focus)

## Variants

- **direction**: horizontal, vertical

## States

- rest (seam + grip)
- hover / dragging (seam lit 3px accent, grip accent)
- focus-visible (look's focus ring round the grip)
- folded (pane at 0, grip ink-3; Enter unfolds)

## Keyboard

- ← → (↑ ↓ stacked) by 5%, Shift by 10%
- Home / End to the limits
- Enter folds a collapsible neighbour

## Motion

The seam and grip light at once on hover or press and fade over --pui-motion-out; panes follow the pointer with no easing; focus is never animated.

## Props

| Prop | Type | Default | Description |
| --- | --- | --- | --- |
| `label` | `string` | — |  |
| `direction` | `"horizontal" \| "vertical"` | `"horizontal"` |  |
| `onLayoutChange` | `(sizes: number[]) => void` | — |  |
| `storageKey` | `string` | — |  |
| `ResizablePanel` | `{ id, label, defaultSize?, minSize? (px), maxSize? (px), collapsible? }` | — |  |
| `style / ref` | `CSSProperties / native Ref` | — |  |
| `classNames` | `ResizablePanelsClassNames` | — |  |

## Import

```tsx
import { ResizablePanel, ResizablePanels } from "@/components/resizable-panels/resizable-panels";
```

## Get it

Resizable panels is part of Beamline: 190 React components and screens your coding agent (Claude Code, Codex, Cursor or any MCP client) installs into your app through Beamline's MCP server, as a ready-built package or as plain React source you can change. $49 one payment (regular $200), no subscription, a year of updates, one licence for your whole team. [Get Beamline](https://beamline.io/checkout?pack=complete) · [Connect your agent](https://beamline.io/connect)

## More in Layout

- [Accordion](https://beamline.io/components/accordion): Topics that open in place, one at a time or several: FAQs and settings sections; each header is a button and the panel's height follows its content.
- [Aspect ratio](https://beamline.io/components/aspect-ratio): Holds media, video and embeds at a fixed width-to-height ratio while the layout resizes.
- [Bezel](https://beamline.io/components/bezel): A double-bezel frame: an outer shell with a hairline, a small gap, and an inset panel with its own edge, so a preview, chart or media reads as set into…
- [Card](https://beamline.io/components/card): A record or a small group of related content and actions: optional media, avatar, title, status, action, meta, free content and a Details toggle; plain…
- [Carousel](https://beamline.io/components/carousel): A row of slides that snap into place: swipe on touch, drag or the arrows with a mouse, ← → when focused, or the dots; optional autoplay that pauses and…
- [Collapsible](https://beamline.io/components/collapsible): One region that opens and closes in place from its trigger, its height animating to the content.
- [Direction](https://beamline.io/components/direction): Sets left-to-right or right-to-left for everything inside: text and logical spacing flip, and Radix parts read the direction for keys and placement.
- [Expandable card](https://beamline.io/components/expandable-card): A dense card that grows in place when asked: the frame resizes and the clamped preview opens into the full text.
- [Scroll area](https://beamline.io/components/scroll-area): A native scroll region with thin overlay thumbs and edge fades that show only where more content waits; thumbs can be dragged or clicked.
- [Separator](https://beamline.io/components/separator): A hairline between groups, horizontal or vertical; hidden from screen readers unless it carries meaning.
- [UI root](https://beamline.io/components/ui-root): Makes a region of any app a Beamline root: theme, brand and direction for everything inside, and a matching layer at page level where its menus, dialogs…