KeyEvent 
    These events are fired when a key is pressed or released. Do not use these events to detect characters being typed (use KeyTypedEvent).
There is no simple relationship between KeyEvent and KeyTypedEvents, it's complicated, and platform dependent. For example, on my laptop, I can generate a KeyTypedEvent for the degree character °, by holding down CapsLock and pressing O twice. (On Linux, I've set CapsLock as my Compose key, which combines the next 2 keys pressed into a single character).
Constructors
Properties
Either EventType.KEY_PRESSED or EventType.KEY_RELEASED
Holds state information for the Shift, Control, Alt and Super keys. See isShiftDown, isControlDown, isAltDown, isSuperDown.
For events of type EventType.KEY_PRESSED, which are generated due to a key is held down.