public function _fields() {
		$fields = apply_filters( 'pum_shortcode_fields', $this->fields(), $this );

		if ( $this->has_content ) {
			$inner_content_labels = $this->inner_content_labels();

			$fields[ $this->inner_content_section ]['main']['_inner_content'] = array(
				'label'    => $inner_content_labels['label'],
				'desc'     => $inner_content_labels['description'],
				'section'  => $this->inner_content_section,
				'type'     => 'textarea',
				'priority' => $this->inner_content_priority,
			);
		}

		$fields = PUM_Admin_Helpers::parse_tab_fields( $fields, array(
			'has_subtabs' => $this->version >= 2,
			'name'        => 'attrs[%s]',
		) );

		if ( $this->version < 2 ) {
			foreach ( $fields as $tab_id => $tab_fields ) {
				foreach ( $tab_fields as $field_id => $field ) {
					/**
					 * Apply field compatibility fixes for shortcodes still on v1.
					 */
					if ( ! empty( $field['type'] ) && in_array( $field['type'], array( 'select', 'postselect', 'radio', 'multicheck' ) ) ) {
						$fields[ $tab_id ][ $field_id ]['options'] = ! empty( $field['options'] ) ? array_flip( $field['options'] ) : array();
					}
				}
			}
		}

		return $fields;
	}