Ever seen this?
Sometimes a strange white box appears with a cross in the middle. This is actually a mini-control panel for controlling X-Plane with a mouse. It pops up when your joystick/yoke is either missing or faulty.
Dragging the cross with the mouse operates the turn and pitch controls.
The square disappears when you connect a Joystick or Yoke, even when X-Plane is running.
If it appears sporadically, it’s usually a sign of a break in the mouse USB cable or plug.