You can easily expand/collapse each level in the outline by using numpad plus and minus. You can walk through a parent/child data(nested) by using left and right arrow. For example: clicking a shoulder bone. You can keep pressing right arrow to follow thru the child bones. If you have multiple children it will follow the first child. You can go thru it with right arrow or use down arrow to move to the next one. Note: right and left arrow will automatically expand and collapse hierarchy.
