Thank you Drakoz, that's what I was expecting anyway...
I was trying to save the joystick keys by engaging a mode from the keyboard, but I think I can achieve the same using the TEMPO feature on a given joystick key for mode engagement, with a 3sec press for example, and then have all keys will be available for that mode... will try this. Maybe it's also a good opportunity to try that audio beep solution you mention in another post to announce the mode change...