In all of my projects I use a side-chain trigger on a track with no direct output that sends to a Cubase compressor on a group channel. I always set that trigger track on Solo Defeat, so when I need to check other tracks in Solo that are routed to that group channel, the side-chain compression keeps working.
After I save, close and reopen the project, the Solo Defeat setting gets forgotten and I need to re-enable it. It is a very small nuisance, but I thought it mention it anyway.
I’m on Cubase Pro 9.0.40, Windows 10.