Refreshing or Closing of a Library or a Project
When you right-click on a Library or Project in Project Explorer you will also see the option to Refresh, Save or Close the Library or Project.

Closing a Library (or Project) removes its content from Project Explorer memory (i.e.the constituent elements contained in either the Library or Project are no longer visible in Project Explorer but the Name of either the Library or the Project remains visible in Project Explorer.
When Wiring Planner is closed and then reopened it opens with the same configurating files that were previously open.
Related Topics:
Opening a Library or a Project
Opening Wiring Planner Files from File Explorer