Hi Tom,
Thanks for writing in! First of all, make sure that you’re fully updated and using latest X compatible versions by referring to our guide here (https://theme.co/apex/forum/t/troubleshooting-version-compatibility/195).
Also make sure that you’re using the latest version of WordPress core as well by referring to the following link (http://wordpress.org/download/).
If you’re still having issues, try switching to another theme to see if you’re experiencing X theme related issue. If it is theme X theme related and if you’re using a child theme, try switching to your parent X theme and confirm the issue as well.
If you confirm the issue to be related to X theme, please provide us with exact steps to reproduce the issue, so that we can test it on our end and assist you.
Thanks!