protected void OnKeyRelease(object sender, KeyReleaseEventArgs args)
{
GtkKey key = (GtkKey)Keyval.ToLower((uint)args.Event.Key);
_pressedKeys.Remove(key);
}
protected void OnKeyPress(object sender, KeyPressEventArgs args)
{
GtkKey key = (GtkKey)Keyval.ToLower((uint)args.Event.Key);
_pressedKeys.Add(key);
}