| Parameter | Description | 
|---|---|
| id | The item ID. | 
| expandAllChildren | Whether the whole hierarchy under that item will be expanded. | 
| refresh | Whether to refresh items or not. Set to false when doing multiple operations on the tree, to only do one RefreshItems once all operations are done. | 
Expands the item with the specified ID, making its children visible. Allows to expand the whole hierarchy under that item.