Some entries work the same way as discussed in the edit menu of the trackwindow. Only the entries that is special for the pianowindow is described here.
Cut, Copy, Paste
Shift
Quantize
Left - Right, Up - Down
Cut is like Copy + delete.
Moves selected events to the left or right. The amount is snaps, which can be adjusted in the settings-menu.
Exchanges the position of selected events. Try it.