8BitDo FCPro works in dash and games, but not in shell sections

[American horizon]

Hi
My conf:
Raspberry Pi3
Retropie 4.3
Emulation Station 2.6.4 RP
8bitdo fc30pro connected via usb

I've configured the pad through the input menu of the "dashboard"... I mapped A key with the B button of the joypad and viceversa... Other buttons settings are pretty much the same as layout (select, start, triggers, dpad, etc...)

All works ok into the dashboard and games, but when i try to open a shell, such "Retropie Setup" i'm unable to use the joypad in a correct manner.
I'm able to go up and down, but is impossible to enter into a section (with keyboard i do it pressing ENTER).

If i press start it simple switch between "ok" "exit" and "help" comands at bottom of the window.... No joypad button seems to accomplish the "ENTER" command!!

The strange thing is that if i remap the input config, assigning A key to A button and B key to B button, finally i can go into the shell and enter into sections pressing START....

Senseless!