Originally Posted By: Brille
... it is even possible to display an Ebmaj7 and a D#maj7 simultaneously in one piece or even in one bar. That's a bit bizarre, but it works, I just tried it out.
Example:
- Select key "C"
- Enter Ebj in the first bar, then there is an Ebj7.
- then set the key of the piece to "E" (without transposing)
- Then enter D#j in the next bar and voilá: D#j7 appears next to Ebj7.
...

Usually it's even possible to mix enharmonic chord symbols such as EbMaj7 and D#Maj7 simply via editing - no need to get engaged in any key changing gymnastics.

There is one use case, though, where this approach won't work -> whenever some transposition is active, as is often the case with saxophone players, say, mixing of enharmonic chord symbols is not supported.

Originally Posted By: Brille
I have tried to find out why Band in a Box sometimes turns an entered Ebj7 chord into a D#j7 when entering chords.

That's most likely the case whenever transposition is active and certainly may lead to frustration.

This use case might deserve attention with some future update.

Martin