I filed a bug report:
https://bugs.launchpad.net/ubuntu/+sour ... ug/1911984

I just did a quick check by doing a clean .deb install of SH3d in Ubuntu 18.04 (I run myself 20.04) and there it is also set to false. So who to contact to make them aware of the repository bug? I will see if can file bug report to these packages.

And by the way, great program! I'm using it for ...

I think I found the solution for the "greyed-out top" view icon problem.
/usr/share/sweethome3d/sweethome3d.sh script contains, upon install via repository, the java option:

-Dcom.eteks.sweethome3d.j3d.checkOffScreenSupport=false

set it to true and top view icons behaves normally again.

Please ...