Hi Chris,
Thank you very much for your advice to look for 32 bit MIDI monitors, too!
Meanwhile I installed MIDI OX and it shows every event on any MIDI input device. But so far I am too silly to figure out how to monitor the output devices for events sent from Nuendo to the device. MIDI OX recommends to install MIDI Yoke, too, which should be able to re-route the output from Nuendo to MIDI OX, but Win 8.1 does not let me install MIDI Yoke (a legacy device driver).
Today any incoming MIDI events results in 24 (!) midi out peaks in the MIDI Activity section of the transport window in Nuendo.
So I think I need further help on how to monitor the MIDI events sent from Nuendo…
Best
Stefan