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[`Workspace`](Workspace) › [on('active-leaf-change')](Workspace/on('active-leaf-change').md)
## Workspace.on('active-leaf-change') method
Triggered when the active leaf changes.
0.10.9
**Signature:**
```typescript
on(name: 'active-leaf-change', callback: (leaf: WorkspaceLeaf | null) => any, ctx?: any): EventRef;
```
## Parameters
| Parameter | Type | Description |
| --- | --- | --- |
| <code>name</code> | <code>'active-leaf-change'</code> | |
| <code>callback</code> | <code>(leaf: </code>[`WorkspaceLeaf`](WorkspaceLeaf)<code> | null) => any</code> | |
| <code>ctx</code> | <code>any</code> | _(Optional)_ |
**Returns:**
[`EventRef`](EventRef)