When using both http and https on the site, it is not possible to change the theme on https pages.
This is easily fixed by changing this line in 'get_cookie_name()':
$hash = 'wordpress_tts_theme_' . md5( get_home_url() );
$hash = 'wordpress_tts_theme_' . md5( home_url('','http') )
Could you include this change in the next update?
Except from this, plugin is working perfectly! Thank you!