Agree that Drum Maps could use a serious makeover.
You might try setting Cubase to always run as administrator.
Just yesterday I discovered something new (to me) about Drum Maps and the Key Editor. I was playing around with making midi drum loops in another program and then importing the midi files into Cubase. Something wasn’t quite right so I opened the MIDI Part with the Key Editor to see how it looked there. I was surprised to find that the notes showed the name of the drum on them - much like how lyrics show on the notes. Moving the notes up and down changed the name to reflect the names from the Drum Map. Since some tasks are easier to do in the Key vs. the Drum Editor this opens the door to using both without adding confusion about what drum is being played.