Is there a shortcut key to control the Open property of cell?
I have find an answer which is really helpfull: AutoCollapse[] function (Hiding inputs with specific function)
Also have find the way of add shortcut button (Create custom shortcut to change font color).
Through change: MenuItem["&Open", CellOpen->Toggle, Scope->SelectionCell], to, e.g. MenuItem["&Open", CellOpen->Toggle, Scope->SelectionCell, MenuKey["0", Modifiers->{"Control"}]]
While not directly a shortcut, you can always traverse the menu: Alt c p o
Command
+'
. Not the same but similar and possibly useful for similar purposes. $\endgroup$ – Szabolcs Aug 29 '18 at 8:20