making money in medieval II

Question: blinking items on the settlement details page, what exactly do they indicate again?
Is it indicating that I'm not getting the full possible amount of trade because of rebels or enemies?
Is it indicating that I will get this florins extra when I build a certain building?

I have a blinking 800+ florins on my detail page for Lisboa. There're no pirates nearby and land trade to Toledo and Leon isn't blocked either. I'm also not building anything there now.

R'as

I think merchants from other factions who are trading on resources of other factions' settlements should be taxed or pay some sort of fee to the settlements that is associated to that resource, regardless of the stance with the faction that the merchant belongs to. But that might not be historically accurate though for this thing to be implemented in the game in the future, but its just an idea, because i dont notice that during my current campaigns.