Assigning two controller inputs to the same key doesn't work

[neuviemeporte]

Tried assigning both the L and R shoulder buttons on my controller to the same key for blocking in a fighting game. Unfortunately, only the latter button works, the former is ignored.

Seems to be the case for any key assigned more than once in the Control options - only the last entry is considered.

[neuviemeporte]

Moreover, after a key has been assigned to a controller button, it is not possible to use it from the keyboard anymore. Keyboard keys that have been assigned to controller buttons are either ignored or assigned to other keys seemingly at random.