User stitch libraries created in version 2 have symbols based on fonts. These stitch libraries can still be viewed but can no longer be edited in version 3.
They can also still be used by any chart files that are already using them. However they are no longer accessible via the New Chart Diagram or Edit Diagram Properties dialogs. We recommend that you migrate your version 2 user libraries to the version 3 format. You should also set your default stitch library to be a version 3 stitch library. See Migrating a version 2 stitch library to version 3 for more details.