Item actions
Select an item before using a shortcut (click on a line containing a box to highlight it). New item →Enter
New sub-item → Shift
+ Enter
Delete selected item → Delete
Navigation
Select Item →Left-Click
Context menu → Right-Click
Item navigation → ↓
and ↑
Collapse/Expand → ←
and →
Remove selection → Escape
Other
Toggle wallboard mode → Z
Undo → Cmd
+ Z
Open System-Info Dialog → Shift
+ I
Open Help Dialog → Shift
+ /
Play a BigPicture game → Shift
+ G