React · SwiftUI · agent guides
Split pane
Two places with a divider you can move: dragged one to one, it snaps to the default size or shut on the part spring; keys step it on settle.
Use it for
- A list beside its details, a canvas beside an inspector, an editor over its preview: two places whose balance people change.
Don't use it for
- A sidebar that only opens and closes (use the sidebar place), or content that should reflow instead (use a responsive layout).