the screen fading option was set to be true by default. It was removed from the
option menu.

To speed up validation, it is temporarily set to false in the dialog validator.

When the validator now crashes, the flag is saved as false apparently. (after
the validation is done it would be set to true again, but we didn't reach that
point), and there is no way to manually set the flag as true again.

there should be some way to fix this (maybe by adding another check and another
validator-only fading setting?) without reintroducing the option in the setting
menu.

if (!screen_fading && !benchmark_enabled)
    screen_fading=TRUE;

On first processed lines?

Resolved with 6834b7f8be64cb4c8c3c0898e798635c974d3082.

We don't ever save config in case of error.