Since Drupal 8.4.0 → node edit forms have not been using a dropbutton. However, the Save & Edit module provides an "Integrate into dropbutton" setting that is enabled by default. Leaving this enabled on module installation leads to improper theming of the Save & Edit button.
On module installation, the "Integrate into dropbutton" checkbox is checked by default on the module settings form under /admin/config/save_edit/settings. Leaving this checked, enable Save & Edit functionality on any node type at the bottom of the settings page. When next editing content of that type, the Save & Edit button will be improperly styled.
This visual bug will differ depending on the admin theme.
Seven:
🐛
Save & Edit button looks like two overlapping buttons
Closed: duplicate
Claro:
🐛
Alignment issue
Closed: duplicate
Remove support for Dropbutton from the Save & Edit module.
Removes the "Integrate into dropbutton" checkbox from the Save & Edit settings page.
Fixed
1.0
Code
I'll leave this issue open for a week or so to give people a chance to test these changes and catch any issues, but it should be straightforward enough that it's good for a stable release.
Automatically closed - issue fixed for 2 weeks with no activity.