The per surface filter works really well. Thanks for adding that. (Although I have to rename all my sites once more ;-)
In the only warning mode there surfaces without a warning will still display the vertical separator. Maybe only show the separator if the surface actually has a warning?
One last request: Would it be possible to add aliases for surfaces in the (map-)settings? Some of them are just slightly off or way longer than the rest.
Like nauvis -> Nauvis
And Calidus Asteroid Belt 1 -> Calidus B1
Also I have a suggestion on how to make the design even more narrow.
The totals column does not have a site name, so you could drop the extra column for the surface and just have it once in the totals row.
This might make the display slightly longer if there otherwise wouldn't be a total column (no warnings).
Alternatively put the surface name in the first column instead of "Sites".
I don't know how well this looks, but might be worth a try.
Is this design intended?
Why are most of the surfaces in one group and only the surfaces with totals in their own group?
Either every surface should have the "Site" separator or you can omit it entirely.