Just as a further update for others who come across this thread...
So for instance if the plugin adds a popup dialog with a tinymce button in the post page, if the jquery dialog function is not enqueued then side effects I noticed were as follows:
- items in the 'Published' metabox did not slide open as they should
- this includes the 'status' and 'visibility' fields
So if you suddenly notice that items in the publish metabox do not work, then have look to see if its because jquery dialog has not been enqueued in 3.9