Comment 2 for bug 2046815

This changed with https://github.com/PintaProject/Pinta/pull/613 where I changed the default to "prefer dark", but it seems like Ubuntu's light theme doesn't indicate that the system wants to force a light color scheme.
I've reverted that back to the default with https://github.com/PintaProject/Pinta/commit/347919d57c2537e234308996dab3d76ec450f0d6

There is also now a Color Scheme option in the View menu to explicitly pick a dark or light theme