Problem re-allocating hot key

[hugso]

I recently bit the bullet and bought a new PC to enable my to fly CoD. Haven't flown a lot but overall very impressed with graphics. (Love the cockpit shadows especially). I have allocated a number of functions to switches connected via a BU0836X joystick controller.

I have just tried to re-allocate the cockpit opening function to a different switch. In Controls the new switch is picked up and displayed in the box perfectly OK, pressed Apply, but in game the there is no action with the new switch and the original switch still makes the move. I have tried deleting the hot-key entry, but even with the box blank in Controls the original switch still opens the canopy. Am I missing something?

I am using the game as supplied by Steam, ie not beta patched.

Grateful for any ideas.