The problem is that the 15 button limit is not for DISPLAYED buttons, but order of buttons
if you have in your buttons.cfg file
button1
button2
button3
button4
button5
...
button16
button17
You will only see the first 15. You will never ever see buttons16 and below. No matter your group settings.
You cannot "game" fop2 by having small groups. If you want to display buttons on a group that are in fact in position beyond 15, you must register.
Best regards,
