Can't assign G2 to C3 in pad remote control

[Nico5]

There seems to be an explanation in an older forum thread:

Cannot set remote key in Chord Pads

In Chord Pads the Remote Range is C1 to B1. I’d like to set it C1 to B2. According to the manual you can easily do it through MIDI Learn. But then it says “remote key already in use”. I have Voicings, Tensions and Transpose not activated so those keys should not be in play. So how do I find out which function B2 triggers and how do I unassign that? And do I have to unassign all keys between B1 and B2?