Hey John thanks for trying out the new beta
The categories are like other WordPress categories. For now you can organize your calendars in categories. This hasn’t many applications yet except for organizing calendars and – if you mash calendars together with the Grouped Calendars events source – blend calendars belonging to the same categories. In future we can expand further on categories if we find more use cases for them.
In the calendars advanced tab there shouldn’t be settings pertaining categories, but just adjusting things like timezone, date and time formatting, etc. To use categories with the ‘Grouped Calendars’ events source, the categories must also have calendars assigned to them (just like posts), ie not empty.
As for the widget, it should be possible to have multiple calendars blended together. But you need to create such calendar first. Add a new calendar, then select ‘Grouped Calendars’ as Events source. You can choose which calendars this calendar should blend together (either individual calendars or calendars belonging to categories). Once this is done, you can display this calendar mix either as a shortcode, or as a widget.
Please let me know if there’s anything not working as it should or if you find something unfriendly or a missing feature.
There was an user that complained the contents of his old feeds were not imported in the new version (the text and shortcodes in the post editor) – were the feeds correctly imported for you, or did you try a fresh install?
Thank you!