No Sunset Time

[Guy]

I started using f.lux again in November last year, and it made a significant improvement to my sleep.
But now that it's spring, I get no 'sunset' time at all.

It goes straight from 'daytime' to 'bedtime', skipping over 'sunset' entirely.
I realize this is a consequence of being relatively far north, but would it be possible to set a minimum duration of 'sunset' time in f.lux?
So that there is always at least an hour of it before the screen turns red.