wouldn’d it be nice to
- open folder “exclusive” > and close all other opened folders
- by new toggling shortcut
I guess that’s already possible with the Project Logical Editor (creating a preset to be used with keyco or within a macro). Can’t tell you how ad hoc because PLE is something that works different from my personal Brain Logic Editor but nearly any weird thing I tried to make it do it does - after lots of experimenting 
yes, ist works as Martin described in wish: open group folder "exclusive" - Cubase - Steinberg Forums