Your key assignment makes complete sense! I commented out the changes and got your result described above. Unfortunately my gamepad (Dpad neither sticks) doesn't respond with your key mapping, I think it's my hardware, a $5 Controller for Windows so I tend to turn off the quickmenu. Thanks for your answer and also for the "index_of_gamepad_keys.txt" file. I need to look much deeper into this ;)
Kind regards
Tom