I’m experiencing many of the same issues. Unfortunately, I have 10 sites that need to be upgraded and can’t afford to spend the time to modify every theme.
Already tried inactivating all plugins and that didn’t work. I also tried using the Hotfix plugin that has helped in the past, but no-go. This is a major issue as I have customers who maintain their posts and if the image insertion, quick edit and tag addition doesn’t work, I have a big problem. Hopefully the WordPress community can release a patch or update soon.
This “problem” is affecting two of my sites and I’m very nervous about updating any more of them.
