<div class='sourceset sourceset-common'>Common</div>

```kotlin
class ThreePaneScaffoldHorizontalOrder
internal constructor(
    internal val firstPane: ThreePaneScaffoldRole,
    internal val secondPane: ThreePaneScaffoldRole,
    internal val thirdPane: ThreePaneScaffoldRole,
) : PaneScaffoldHorizontalOrder<ThreePaneScaffoldRole>
```

Represents the horizontal order of panes in a `ThreePaneScaffold` from start to end. Currently
this class only have two possible instances, i.e. `ListDetailPaneScaffoldDefaults.PaneOrder` and
`SupportingPaneScaffoldDefaults.PaneOrder`, which will be used internally by
[ListDetailPaneScaffold](/jetpack-compose/androidx.compose.material3.adaptive/adaptive-layout/composable-functions/ListDetailPaneScaffold) and [SupportingPaneScaffold](/jetpack-compose/androidx.compose.material3.adaptive/adaptive-layout/composable-functions/SupportingPaneScaffold) respectively.

## Functions

<h2 id="get-index">get</h2>

```kotlin
operator fun get(index: Int) =
        when (index) {
            0 -> firstPane
            1 -> secondPane
            2 -> thirdPane
            else -> throw IndexOutOfBoundsException("Invalid pane index $index")
        }
```