Script favorites not persistent

In FM 13.0.5.547 the scripts in the script library (favorites list) disappear after some time.

1. I define a favorite script, then close FM
2. Start FM again: (withing a minute) the script is still in the catalogue.
3. I closeFM
4. After a while (about 5 min) I start FM again
5. => Tthe script is no more in the catalogue!

Where the heck is the catalogue stored?
Who may delete the catalgoue?

Klaus Daube