Default field templates is not applied (by default)

Here is a patch that works for me.

Thank you, protostruct.

Your patch works for me.
Attaching the same path with minor fixes.

Hi Ruslan, you are welcome.
I just want to point out that the additions in your patch are entirely unrelated to this issue, mostly formatting related. Why the changes to ds_theme_suggestions_alter? Please put then into separate issues and explain the changes.

When doing it like this, there is no need to store the default field template configuration for every field formatter by default (once touched and saved). But how to properly optimize it?

Setting $default_field_function in ds_field_template_settings_form and ds_field_formatter_settings_summary_alter always to 'default' gives "Field template: default" a different meaning.

To be complete, there should also be the full field template configuration form on the DS settings page.

Quick testing revealed that this doesn't seem to work indeed.

When setting it to say 'minimal', the summary in the interface shows 'minimal' which is kind of ok. But you could also expect that it would show something like 'Default (minimal)'. Even setting it to 'Default' doesn't trigger this. So really confusing.

Wow, this is a pretty major bug. I noticed it because some fields were getting the right CSS and others weren't. I have applied the patch from #3 and initially it seems to work. I don't quite understand the problem reported in #8.

Checked again, this seems to be working fine now, probably fixed somewhere else.