I'm also talking about SPPB3. This problem has been around for a long time and it is not being solved in any way.
A gray background will not solve the layout problem. It is necessary to remove the addon from the breakpoint, as it is now happening with the section. If you hide a section at a point, it disappears and does not interfere with layout. And the addon remains and takes up space breaking the entire layout.
If you are referring to the fact that there will be confusion with hidden addons, then you have a wonderful layers tool where everything is clearly visible and you can always go to the hidden addon settings
This really interferes with the layout of mobile versions, where everything is so small, and even hidden addons are not removed.
https://disk.yandex.ru/i/epYuVN5DQsmgyA
https://disk.yandex.ru/i/iObqtAUb4Pi6pw
https://disk.yandex.ru/i/Fnw7UGj34tP1gg
This is a real headache