I have several channels assigned to a Midi CC that I no longer need. I do a Right-Click|Forget on the channel. If I Right-Click on it again, it appears to be 'forgotten'... however, if I exit DMXIS, then restart it- I see the Midi assignment is still there.
When I look at the dmxconfig.xml file, I can see it isn't being updated when 'forget' is selected.
To work around this I edited the dmxconfig.xml file directly.