Moving main slider all the way to the right is very buggy
If it's daytime but f.lux is in Bedtime mode, then moving the slider all the way to the right selects the Daytime color. Also, hovering over the f.lux window in various locations makes the text next to the menu very buggy. It seems like it doesn't know which message to display.
If it's nighttime and also in bedtime mode, then the only thing that happens when moving the slider all the way to the right is, f.lux doesn't know which message to display when moving the mouse around.
Taking f.lux out of bedtime mode makes f.lux work just fine.
I remember reporting this months ago, but I just haven't checked to see if it was fixed.