To add a new category to the drop-down lists, click "Preferences" in the "View" menu. Switch to the "Database" tab. Press "Categories" button. This will open a dialog box that can be used to add, remove or reorder categories. To create a new category, type the name at the bottom of dialog and press "Add" button.
When finished customizing categories, don't forget to press OK in both dialogs to save your changes.
