You could try changing the time to night. That makes the symbol orange so it might be easier to see. If you don't see it, you can still try clicking near the center of the windshield until the control box comes up. It's easier to see than the single plus sign.
If you think X-Plane is incorrectly registering a joystick & disabling mouse input, please upload your log.txt found in the main X-Plane folder and a screenshot of your Joystick & Equipment Axis tab.