Every OBO ontology contains a set of categories. Terms in the ontology can be assigned to one of the categories in that set (see An Introduction to OBO Ontologies, and Text Editing for more information on how to assign entities to categories).
The built-in Category Manager Plugin allows users to manage the set of available categories. To access the Category Manager Plugin, choose "Category Manager Plugin" from the "Plugin" menu:
The Category Manager Plugin window will appear:
Any changes made in the Category Manager Plugin are not saved until the "Save Changes" button is clicked. If changes are made and the window is closed, the changes will not be saved. To revert to the last committed version of the category set, click the "Revert" button.
To edit an existing category, click the category to edit in the list on the left. The category editor panel will appear:
Categories have two attributes: a short identifying name and a longer descriptive name. To change the category name, click the category name in the text field and type a new name. To change the descriptive name, click the category description in the text field and type a new description.
To delete an existing category, click the category to delete in the list on the left. Click the Del button to remove the category.
Note that a category that is assigned to a term cannot be deleted. If a category is deleted that is still in use, a warning will appear when the "Save Changes" button is pressed. If a category must be deleted, first search the ontology to make sure that the category is not in use.
To add a new category, click the "Add" button. A new category will be created with the default name "NEWCAT" and the default description "<new term category>":
Edit the name and description as described above.