I used to be able to display my main project on 1080 main screen, mixer on another screen 1600X900 and channel strip/VSTs on third screen and used to keep the settings the next time I opened Cubase. Recently bought 21X9 1440 screen for the project and wanted to display the mixer on the 1080 monitor permanently but it defaults to the main screen every time and the mixer goes behind the project window. Workspace settings either global or project does not seem to do what it is supposed to do! Saw some videos on YT saying in order to keep settings memorized you should not maximize these windows but it worked fine for me in version 10.0.50, not in 10.5
This is an known issue since the new Workspaces has been implemented.
Thanks for posting this - I’ve been scratching my head about this too since getting to 10.5 on Mojave.