To reproduce:

- open the Rich Editor Demo
- type or paste some text
- select File -> Save, choose a new file
Expected:
- file is saved
Observed:
- file is not saved

Also,
- File -> Open should set a *.rich file filter as the first entry.

Another issue with File -> Save As adding a duplicate extension is a product bug in FileChooser, see https://bugs.openjdk.org/browse/JDK-8352298