## Managing the Focus
The TreeList component is a container that consists of 2 logically separated structural elements:
- Toolbar (`role="toolbar"`);
- Tree Grid (`role="treegrid"`);
Each of them is part of the page tab sequence and can be navigated to using the `Tab` key of the keyboard.
The `Toolbar` implements the keyboard navigation specification for a ToolBar component.
The below description focuses only on the `Tree Grid` part (the element with `role="treegrid"`) of the composite component.
## Tree Grid Focus
The Tree Grid is a single tab stop component. Upon focusing the Tree Grid, the initial focus is set to either the previously focused cell (if any), or the first data (`| `) cell in the Tree Grid. The change of the focused cell should be implemented using one of the following two techniques:
- Roving TabIndex components Practice for managing the focus. Meaning that going through the cells will update the tabindex of the cell.
- Active descendant - keeping the focus always on the Data Grid and using the `aria-activedescendant` on the Tree Grid element which points to the id of the currently focused cell.
If a cell contains only one focusable element that does not itself require arrow keys for its inner navigation - focus goes to that element instead of its parent ` | `.
If column header cells do not provide functions, such as sort, filter, or column menu, they may not be focusable.
If the TreeList contains no items (empty TreeList), the `No data` element in the TreeList should be focused. That applies also for the scenario when the last item in the Grid has been deleted.
## Keyboard Shortcuts
The TreeList implements the same keyboard shortcuts as the Grid component. In addition to that, here is the appropriate shortcut to expand/collapse a row:
| Shortcut | Behavior |
| -------- | -------- |
| `Enter` | In expandable and non-editable cell - expands or collapses the item. |
## Resources
[ARIA Authoring Practices: Treegrid Pattern](https://www.w3.org/WAI/ARIA/apg/patterns/treegrid/)
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