[ Flags ]
public enum ModifierType
A set of bit-flags to indicate the state of modifier keys and mouse buttons in various event types.
Typical modifier keys are Shift, Control, Meta, Super, Hyper, Alt, Compose, Apple, CapsLock or ShiftLock.
Like the X Window System, GDK supports 8 modifier keys and 5 mouse buttons.
Since 2.10, GDK recognizes which of the Meta, Super or Hyper keys are mapped to Mod2 - Mod5, and indicates this by setting
META_MASK in the state field of key events.
Note that GDK may add internal values to events which include reserved values such as
GDK_MODIFIER_RESERVED_13_MASK. Your code
should preserve and ignore them. You can use MODIFIER_MASK to
remove all reserved values.