Can't fire and jump with the keyboard at the same time. GamePad works fine

Question

Im confused. Using code like this

input(event): 

    #bound to spacebar and game controller button a. 

    if event.isactionpressed("jump"):

        do stuff..

_process:

    #bound to ctrl and game controller button b. 

    Input.isaction_pressed("fire"):

        do stuff

If using the game controller I can hold down fire and press jump as many times just fine. But on the keyboard if I hold down ctrl and press space I don't jump at all. If I hold down the fire button on the controller I can press space on the keyboard just fine.
Whats going on?

Comments

This must be hardware related. I changed jump to "z" and fire to "x" and everything works fine.

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Does this happen if you bind, say, A instead of Ctrl to shoot?

Answer 1

Is something called ghosting, more about ghosting here:
https://www.microsoft.com/appliedsciences/antighostingexplained.mspx