Hi Nico,
Thank you for the screenshot. The cookie errors appear to be unrelated.
In the latest SiteOrigin CSS we’re using the WordPress version of CodeMirror (it’s the name of the underlying editor library). This was done for performance and consistency related reasons.
It’s possible you have a plugin installed that’s not compatible with that version of CodeMirror. Can you try disabling all non-SiteOrigin plugins and see if this fixes the issue? You’ll need to clear all your caches after disabling your plugins.
If it does fix the issue, then try re-enabling your plugins one by one until the issue comes back. This procedure will help diagnose which plugin is causing the issue.
Once we know that, we’ll be able to look at what might be causing the conflict and either solve the problem or help you find an alternative plugin.
If you aren’t using a SiteOrigin theme, then you can also try temporarily switching to one of the default WordPress themes to see if the issue is theme related.
Kind regards,
Alex