I actually tested this issue on Debian (buster), Ubuntu MATE 20.04.1, Ubuntu 21.04 (devel) and LinuxMint 20. Following are my observations.
- Debian -
- No issues with Brisk menu (doesn't collapse under root login). Version - 0.5.0-9
- No desktop icons on desktop (no right-click option in desktop) although the .desktop files show under /root/Desktop. MATE release - 1.20.4
- Ubuntu MATE 20.04.1 and LinuxMint 20 -
- Brisk menu collapses for root user. Version - 0.6.0-1ubuntu1
- No desktop icons on desktop (no right-click option in desktop) although the .desktop files show under /root/Desktop. MATE release - 1.24.0
- Ubuntu 21.04 -
- Brisk menu collapses for root user. Version - 0.6.2-1
- No desktop icons on desktop (no right-click option in desktop) although the .desktop files show under /root/Desktop. MATE release - 1.24.1
So, the 'desktop application shortcut not visible' issue is common and possibly related to root user's profile for Caja. It may be specifically disabled (which I do not know).
The brisk-menu issue seems Ubuntu specific as it is behaving fine in Debian (older version). I couldn't test on 18.04, which may also have older version of the package. If so, I will raise a bug report for brisk menu.