Common
```kotlin
sealed interface PaneScaffoldHorizontalOrder
```
Represents the horizontal order of panes in a pane scaffold. An implementation of this interface
is supposed to represent an 1-to-1 mapping between all the possible pane roles supported by the
associated pane scaffold, and those panes' index in the order. For example,
[ThreePaneScaffoldHorizontalOrder](/jetpack-compose/androidx.compose.material3.adaptive/adaptive-layout/classes/ThreePaneScaffoldHorizontalOrder) represents an order of three panes supported by the three pane
scaffold implementations like [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).
## Properties
Common
```kotlin
val size: Int
```
The number of panes in the order.
## Functions
indexOf
```kotlin
fun indexOf(role: Role): Int
```
Returns the index of the given role in the order.
forEach
```kotlin
fun forEach(action: (Role) -> Unit)
```
Performs the given [action](/jetpack-compose/androidx.compose.remote/remote-creation-compose/interfaces/Action) for each pane in the order.
forEachIndexed
```kotlin
fun forEachIndexed(action: (Int, Role) -> Unit)
```
Performs the given [action](/jetpack-compose/androidx.compose.remote/remote-creation-compose/interfaces/Action) for each pane in the order, with its index.
forEachIndexedReversed
```kotlin
fun forEachIndexedReversed(action: (Int, Role) -> Unit)
```
Performs the given [action](/jetpack-compose/androidx.compose.remote/remote-creation-compose/interfaces/Action) for each pane in the order, with its index, in reverse order.