code: func (u *UserInterface) currentMonitor() *glfw.Monitor {
  	w := u.window
  	if m := w.GetMonitor(); m != nil {
  		return m
  	}
  	// Get the monitor which the current window belongs to. This requires OS API.
  	return u.currentMonitorFromPosition()
  }
docs: // currentMonitor returns the monitor most suitable with the current window.
  //
  // currentMonitor must be called on the main thread.