Cities and buildings

[ConjurerDragon]

I´m a bit at a loss regarding buildings.
e.g. in my current game I have two elven cities. In one I have built a harbor. When I go to the 2nd the harbor building is checked as "already existing elsewhere" however I can´t build a shipyard building (that requires a harbor). Or in a monsters city I want to build the tax officies which needs the rat guild - in the other monsters city I can´t build the tax office despite the building list stating that I already own a rat guild in another city...

Does that mean that I always have to build all buildings in one city if I want to build the next building that depends on it?
Or do I miss something like that the cities controlled lands have to be connected to have the buildings interact with those of the other cities?

 

[pickardj79]

Each city's build tree is independent of other cities. To build a shipyard in a given city, you have to have a harbor in that city first. The checkboxes are useful to know that somewhere you already have that building, so if you're only building it to gain it's empire-wide effect (transporting units across water, in the case of a harbor), then you don't need to build it. This is helpful with perks and unit-production buildings.