Melda plugins don't receive the sidechain signal in Bitwig (solved!)

[DarkStar]

... in that case the sidechain signal would need to be routed to the first two sidechain channels (9 and 10 on the track).... The upper screenshot here is the initial view of the plug-in inputs and outputs in Reaper (on a 4-channel track:

Unfortunately, afaik, Bitwig doesn't have this routing capability, or does it?

Sorry, I do not know.