Originally https://core.trac.wordpress.org/ticket/35409
Custom Taxonomies do not show up in the Press This panel. It only shows the common Category & Tags.
In addition, if you use a custom post type for Press This, the Press This panel continues to show regular Category and Tags, even if you do not have any of those taxonomies for the custom post type.
Original ticket includes code to enable PT with a CPT for testing purposes.
Originally https://core.trac.wordpress.org/ticket/35409
Original ticket includes code to enable PT with a CPT for testing purposes.