Why is this Civic's boost bar pink?

Just as Valamas asked about Technologies, why is the boost bar below Mercenaries pink while Civil Service and Medieval Faires are gray? I have boosted all three Civics, and I haven't researched any of them. My only guess would be that the boost to Mercenaries came from a Goody Hut except I definitely have more than eight land combat units.

Note: In the screenshot, I haven't chosen my next Civic to research yet. Going back into the game and choosing one (and switching around) has no effect on any of the bars.

Solution 1:

The pink bar signifies that you are currently researching that boosted civic. Similarly a blue bar on technologies signifies you are researching that tech.

The game automatically selects a civic or tech so you don't waste a turn if you forget to pick a new one