@Admonstrator it appears that this app is conflicting with the "Lazy Load Videos" plugin that you have installed. If I disable that plugin, the fields show up properly.
This is not something that I can fix for you, you would need to contact the author of that plugin. I don't have access to the code there, but an educated guess is that the hook file is not properly calling the parent method, which is preventing my code from running. Feel free to quote me on that to the author, and he can contact me if any clarification is necessary.