Steps to reproduce:

1. Log in to back office.
2. Go to Content / Content structure.
3. Create a new content with richtext field e.g Article.
4. Add 2 custom tags (twitter and facebook) in field 'Body'.
5. Try to edit previously added custom tags.

Actual result:

Watch gif please: https://recordit.co/PFzsjty4Mg

After clicking/selecting custom tag in field body user cannot edit custom tag (the bar with options doesn't appear).

Expected result:

User can edit custom tags.