Timeline view (Tasks): When a group is selected

 Expand the group (Enter or Right Arrow )

Collapse the group (Enter or left Arrow )

Select the previous group (The Up Arrow key )

Select the next group (The Down Arrow key )

Select the first group on the timeline (Home )

Select the last group on the timeline (End)

Select the first item on screen in an expanded group or the first item off screen to the right (The Right Arrow key )