This site is being deprecated.
Please see the official X‑Plane Support page for help.
You can try resetting your preferences to see if something got messed up. Find the X-Plane root folder:
Go to the output folder & move, rename, or delete the entire preferences folder.
Also, make sure your frame rate is over 20 fps. Everything in X-Plane is tied to frame rate so if it drops too low it can take such a long time to respond to mouse clicks or button presses that it seems like they're not working.
This site is no longer being actively maintained.