Forgive me if I don’t understand your objective. I’m not sure what you mean by “regions in the working field.” Are you referring to the Cubase Project page?
Actually you can. You do not necessarily need to open any mix consoles to open the Channel Settings box. Select a track in the project page. Click on the “e” that opens channel settings. Now click on any other track in the project page, and channel settings follows whatever track you clicked on. For routing click on the “targets” in the channel settings window.
(if the “e” isn’t showing up on…for example an instrument track, then that means you have not set up your “track control settings” to reflect the “e” showing up in a track.)
EDIT: Now that I’m thinking about this, I know the instrument track has the option for the “e” but not sure if a midi track has that option?
The “E” is also available in the lower zone. I may be misunderstanding your objective?