That's so very strange... i wonder do you have any Gaming peripherals connected? because for the life of me i cant understand why its doing that. The only final thing is to confirm no USB controllers, joysticks, wheels, etc connected as they can sometimes confuse the game
After that only 2 things i could suggest until i think about it more is.
1 try using a controller if available, almost any usb one will work.
2 try using a different computer.
Both of these aren't exactly the best solution