I have the same thing happening.
Template: Virtue
https://ww.wp.xz.cn/themes/virtue/
JWPlayer plugin – v2.1.13
when I change the template to 2014 the drop down boxes work, but when I change it back to Virtue they don’t work anymore. Other dropdown boxes work, but not in the media page.
If I click Edit More Details, which takes to a page not the hovering javascript window, the dropdown box for image still works.
It seems to be something with the window that pops up when clicking on a media file.
