## Managing Focus

The PivotGrid component is a container that consists of two logically separated structural elements:

* Data Grid (`role="grid"`);
* Configurator (`role="application"`); // TBD

Each of them is part of the page tab sequence and can be navigated to using the `Tab` key of the keyboard.

The below description focuses only on the `Data Grid` part (the element with `role="grid"`) of the composite component.

## Data Grid Focus

The Data Grid is a single tab stop component. Upon focusing the Data Grid, the initial focus is set to either the previously focused cell (if any), or the first data (`<td>`) cell in the Data 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 Data Grid element which points to the id of the currently focused cell.

## Keyboard Shortcuts

### All Grid cells

| Shortcut | Behavior |
|----------|----------|
| `Right Arrow`| Moves focus one cell to the right (if any)|
| `Left Arrow`| Moves focus one cell to the left (if any)|
| `Down Arrow`| Moves focus one cell down (if any)|
| `Up Arrow`| Moves focus one cell up (if any)|
| `Home` | Moves focus to the first cell in the row that contains focus. |
| `End` | Moves focus to the last cell in the row that contains focus. |
| `Ctrl/Cmd + Home` | Moves focus to the first (top-left) data cell in the grid. |
| `Ctrl/Cmd + End` | Moves focus to the last cell in the last row of the Grid. |

### Grid header cells

| Shortcut | Behavior |
|----------|----------|
| `Enter` & `Space` | If the header cell is expandable, toggles the current expanded state. |

### Configurator - TBD


## Resources

https://www.w3.org/TR/wai-aria-practices-1.2/#grid

https://www.w3.org/TR/wai-aria-practices-1.2/#keyboard-interaction-for-data-grids

https://www.w3.org/TR/wai-aria-practices-1.2/#gridNav

https://www.w3.org/TR/wai-aria-practices-1.2/examples/grid/dataGrids.html