[Error] Creating default object from empty value
Having freshly installed and configured the plugin (copied the yaml in /config/plugin), I have this critkey error :

My setup is :
- A regular page "commentaires.fr.md" with, in frontmatter :
---
title: Commentaires
visible: true
---
- A template commentaires.html.twig, with :
{% extends 'partials/base.html.twig' %}
{% block content %}
{% set tag = page.header.user_htmltag|defined('div') %}
<{{ tag }} class="{{ page.header.user_classes }}">
{{ page.content }}
{% include 'partials/comments.html.twig' with {'page': page} %}
</{{ tag }}>
{% endblock %}
I enabled the plugin for the pages :
enable_on_routes:
- '/blog'
- '/critiques'
- '/commentaires'
I'm not familiar with this plugin as Flavio wrote it. When Grav 1.6 is released, we can go back and see about fixing issues on it. Sorry for the delay.
To me, it looks like $header could be null.
@rhukster A big thank you for the quick answer. I thought the plugin was abandoned, but I see that there's still people involved on it (and this is important, given the utility of this plugin). I will be patient. ;) For now, I think I'm gonna disable the plugin and wait for a fix.
@rhukster Now that Grav 1.6 is out, can the team take a look at this plugin? I'd like to use it, but it seems like many are having issues because it's outdated.
I'm testing this with 1.6 and 1.7 and PHP 7.4 and don't see this error any more.