Window
Window class performs the process about a window operation.
Window.isPressModifierKey(keys)
Gets which modifier key is pressed currently. You use for "keys" what combined the following variables by "or".
// ex:
var pressed = Window.isPressModifierKey(Window.SHIFT | Window.CTRL);
Window.SHIFT
Shift key
Window.CTRL
Ctrl key
Window.ALT
Alt key