public RegisterUC(StartWindow recievedWindow)
 {
     InitializeComponent();
     st = recievedWindow;
 }
 public LoginUC(StartWindow st)
 {
     this.st = st;
     InitializeComponent();
 }
 public StartingUC(StartWindow receivedSt)
 {
     InitializeComponent();
     st = receivedSt;
 }