The SCA Library List box contains a list of current SCA libraries.
  When you click MB1 on a library name, the library becomes the
  selected library, for which you can display module and attribute
  information.  You can add libraries to the list or remove libraries
  from the list.

  When you perform queries, SCA searches the libraries in the order in
  which they are listed.  If different libraries contain modules with
  the same name, the module in the library that is highest in the list
  occludes modules in libraries that are lower in the list.