I am having the same issue and it is happening with more plugins, like Locations and Private Topics. The “you have unsaved changes” with the option to save simply does not pop up. Even when I change something else, the settings are not being saved.
Maybe this belongs in Development since the offical plugins do not seem to suffer from this, but OTOH this broke with a Discourse update.
Yes, this is specifically a problem with formkit when enable_simplified_category_creation is enabled, plugins will need to migrate to use formkit and the new data structure.
there’s a working example of this in one of our core plugins, which was migrated here:
you can see how the form structure branches with {{#if this.siteSettings.enable_simplified_category_creation}} and how the form if structured using formkit and data from @outletArgs.form. The old form structure is still there after {{else}} for legacy support.
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