There are multiple problems with the keyboard navigation of grids, that combined make it pretty much impossible to navigate them solely via the keyboard.
- The first time the grid gets focus, it immediately focuses the first cell of the grid. This means that it bypasses the the toolbar completely. The only way to navigate to the toolbar at that point is to navigate backwards, which the user isn't likely to know.
- When the first cell of the grid is focused, it doesn't get an outline indicating that it's focused. This makes issue #1 even more confusing, since not only is focus now where you don't expect it, but there's not even a visual indicator to let you know that's the case.
- After that initial grid focus, if the grid is later refocused, the automatic selection of a grid cell doesn't occur, so it is possible to navigate to the toolbar buttons. However, both the overall grid and the entire grid toolbar are able to receive focus. Neither of these elements can be interacted with, so should not be focusable. In addition, there's no visual indicator that those elements are focused, so again the user has no idea where the focus is.
- If you click out of the grid after using the keyboard to navigate to a cell, the outline around the cell stays, making it look like it still has focus. The way this combines with issue #2, if you use the keyboard to navigate into a grid, then click out, then use the keyboard to navigate back to the grid, when the first cell is focused, it DOESN'T get an outline, but the cell that was last focused DOES still have an outline, so the wrong cell appears focused.