This is part of #378 as it is now a feature included in D8 core (d.org issue):

This was something that tested really well on the D8 UX study, and we should consider adding to Backdrop as well.
User interface changes
- Form validation error messages are displayed below the respective form fields that have triggered them.
- A brief indication of the number of errors, and a link to each error is displayed in the messages area at the top of the page.
Contrib modules
Drupal 7 inline messages module

Drupal 6 (and 7) ife module

Inline Form Errors unofficial and very experimental Backdrop contrib module by @daggerhart:

~~ Advocate for this issue: @klonos ~~
GitHub Issue #:
1040
Recent comments
It's not English. It's Globish :-) (Global + English). Like for Drupal Devel is not an option - I looked style guide but for me, it's not interesting. It's useful but it's just a one page...
Create a new theme - Starter theme
Thank you for your positive response. I guess English is not your first language but it seems like you found the Devel setting for theme debug where it suggests templates and found that useful. You...
Create a new theme - Starter theme
Great. I can confirm this fixed the issue. Thanks.
Disappearing administration bar. Is this a Leaflet or a Backdrop bug?