====How are library imports synchronized?====
It does not get more technical than this I guess. 

But its good to have this documented.

When you load a library in the Simple editor (or in the troopType editor or the officer editor) specific data is read from the library, depending on what kind of library it is. See another article here.

However how does the engine decide if a piece of data in your scenario will have to be replaced or if a piece has to be added?

====Substituting a library?====
First of all. If you reload a library you should make sure you are substituting an existing library.

If you do not substitute a 2nd copy of the library will be added and no replacements of data will take place.

If you do substitute the paragraphs below will explain how will be decided if it concerns a data replacement or addition. 

Condition for all below is that the current library of the data instance is equal to the one you are subtituting. 

====Garbage collection====
If you reload a library, but some data instances have been removed from it, these instances will also be removed from your scenario.

====Substitution Rules====

===SFType===

IF Library ID# of scenario SFType == ID# of the SFType in the library

===Reinforcement Types===

IF Library ID# of scenario ReinfType == ID# of the ReinfType in the library 

AND IF scenario ReinfType Name == ReinfTypeName in the library

NB: Keep in mind it is not possible for TroopTypes from different TroopTypes libraries to share the same ReinfType.

===Historical Units / Models===

IF Library ID# of scenario historical unit/model == ID# of the historical unit in the library

NB: Historical units are updated with their models and units are updated with their historical units

NB: Officers assigned to historical units that have been removed from library are returned to the pool

===Officers===

IF Library ID# of scenario officer == ID# of the officer in the library

NB: Yes officers are kept in the same datatype as historical units and models. 

===PreDef Units===

IF Library ID# of the scenario Unit == PredefID# of the unit in the library 

===People===

IF Library ID# of the scenario People == ID# of the people in the library

NB: The only way to actually add People to the scenario through the Simple Editor is to have them already present in the masterfile (like Universals in VR Ruleset) or import them through loading a historical library or map file.

===Action cards===

IF Library ID# of the scenario action card == Slot# of the action card in the library

AND IF sceon card name == library action card 

===Events===

IF Library ID# of the scenario event== ID# of the event in the library

AND IF scenario event name == library event name 

===Stringlists==

IF Library ID# of the scenario stringlist== ID# of the stringlist in the library

AND IF scenario stringlist name == library stringlist name 

===Libvars===

IF name of the scenario libvar == name of the libvar in the library

AND IF type of the scenario libvar == type of the libvar in the library

AND IF valueType of the scenario libvar == valueType of the libvar in the library

===SmallGfx===

IF Library ID# of the scenario SmallGfx == ID# of the smallGfx in the library

AND IF the file name of the scenario SmallGfx == filename of the smallGfx in the library

NB: SmallGfx are removed from scenario if they no longer are present in library, even if they are referenced in libvars or stringlists.

===Event Pictures===

IF Library ID# of the scenario event picture == ID# of the event picture in the library

AND IF the file name of the scenario event picture == filename of the event picture in the library

NB: Event pictures are removed from scenario if they no longer are present in library, even if they are referenced in libvars or stringlists.

===Hex & Location (map import)===

This follows a special protocol.

You can only load a map file that has the same width X height as the map of the current scenario.

You can optionally load the Victory Points from the map file.

All hex data including landscape type, labels, rivers, roads, 9 areaslots will be overwritten.

All location data will be overwritten.

NB: A map load can also add or subtitute people.