Field content selector
The preferences for this feature are accessible via Library → Library properties → Content selectors and allows you to store often-used words or phrases. This creates the possibility to conveniently make use of them in the entry editor to fill in field content.
To add a new word by using the content selector in the entry editor, you can simply click into the text box for the field for which you configured the selectors. A drop down menu will appear and you can select the keyword of your choice. This mechanism is based on the autocompletion functionality in JabRef (File → Preferences → Autocompletion) . Therefore, you need to have autocompletion enabled in your preferences.
By default, the feature is enabled for the fields Journal, Author, Keywords and Publisher, but you can also add selectors to other fields.
The word selection is library-specific, and is saved along with your references in the .bib file.