public static bool DdcOpen(this IKeyEventArgs e, IDDControl ddc) => !e.ShiftOrCtrl() && e.Up() && !ddc.DroppedDown && (e.Enter() && e.KeyCode == Key.Tab || e.Alt && e.KeyCode == Key.Down);
public static bool DdcClose(this IKeyEventArgs e, IDDControl ddc) => !e.ShiftOrCtrl() && e.Up() && ddc.DroppedDown && (!e.Alt && e.KeyCode == Key.Escape || e.Alt && e.KeyCode == Key.Up || e.KeyCode == Key.Tab);