Interaction logic for signup.xaml
Inheritance: System.Windows.Controls.UserControl, IVirtualKeyboardInjectable
        public static void open_signup_window(double pos_x, double pos_y)
        {
            if (window_manager.signup_frames.Count + 1 > configurations.max_signup_frame)
                return;

            window_frame frame = new window_frame();
            signup s = new signup();
            s.parent = frame;
            s.user_pin.parent = frame;
            s.load_window();
            frame.window_content.Content = s;

            window_manager.signup_frames.Add(frame);
            open_window(frame, pos_x, pos_y);
            frame.hide_change_view();
            frame.set_title("Sign up");
            frame.set_icon(configurations.img_signup_window_icon);
        }