GIF (problem) - Notice that the "Paste" command becomes unavailable after the "Activate Next Part" command (in Generic Remote) is triggered.
(happens only of the “Activate Next Part” command is triggered by the Generic Remote; if it’s triggered by a keyboard command, there’s no problem)
How to replicate the issue
Go to “Studio/Studio Setup…”, add a generic remote (Add Device/Generic Remote) and make it look like this:
In an empty project:
1 - Create two MIDI tracks
2 - Draw a MIDI part and copy it to the other track
3 - Select both parts and hit return (make sure that the Key editor opens in a separate window)
4 - Draw a note and copy it (“Edit/Copy”)
5 - Trigger the “Untitled” Generic Remote entry (to which you assigned the “Activate Next Part” command).
Result: Open the “Edit” menu and notice that the “Paste” command became unavailable (in unavailable). The other command (“Activate Previous Part”) causes the same issue.
"Acoustic Feedback" also causes the issue (see GIF)
1 - Assign a keyboard command to “Activate Next Part”.
2 - Program a MIDI message to trigger that keyboard command using Bome MIDI Translator Pro, midiStroke, or MidiPipe.
Use Cubase 10 (there, the problem doesn’t occur)