public function afterSwitchTheme() {
		$this->clearCache();
		foreach ( $this->getTabs() as $slug => $subclass ) {
			/** @var \Pressbooks\Options $subclass (not instantiated, just a string) */
			$current_options = get_option( "pressbooks_theme_options_{$slug}", [] );
			if ( ! empty( $current_options ) ) {
				update_option( "pressbooks_theme_options_{$slug}", $subclass::filterDefaults( $current_options ) );
			}
		}
	}