I have extended LayoutDefault to add an 'additional classes' option as per
https://www.drupal.org/docs/8/api/layout-api/how-to-register-layouts#usi... →
Within validateConfigurationForm any set errors will not appear due to the lack of a status messages section.
I'm thinking should LayoutDefault handle form validation errors?
Closed: cannot reproduce
11.0 🔥
layout_builder.module
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
Ran a test of this from the latest 11.x branch. I implemented validateConfigurationForm on the TwoColumnLayout class that set a error, and its displaying correctly.
This appears to not be an issue and it has been many years since the last update, so I'm closing this.