Hi,
Problem was related to our footer.php which did not call wp_footer();
So this was not a bug from your plugin but from us.
Unfortunatley in the events calendar pro widget there are 2 problems.
a) widget-calendar.js calls in line 37 $( ‘.tribe_mini_calendar_widget’ ). In your original template there is no tribe_mini_calendar_widget class defined. Thats why i could not jump between the months. I changed this in the meanwhile to $(‘body’) to be sure it works for now.
b) the next month >> creates a wrong date at initial call. it wants to jump from january to march instead of feb. After it jumped to march it works fine backwards and forward. Couldn′t find a fix for it so far because it seems that inital links are generated by a php function (but im not sure yet). If you would have a small advice or fix I really would apreaciate. (funny fact: same problem on your demo site as well https://wpshindig.com/event-widgets/ )
Best regards,
MrFeedbackAUT
