relatedTo working for one category group but not another

Question

I'm trying to show a list of entries related to the same category on a page that contains a single entry. I have two category separate category fields in the entry, both with one category each selected in them. The two category groups are named eventType and venue. The code below successfully shows a list of entry titles for one category group but not the other, and I can't seem to find out what's going wrong.

The code below works for the eventType category group (it shows all the entries related to eventType). But when I swap out eventType for venue, it returns my else statement.

I'm new to Craft (it's great!), so maybe I'm going about this all wrong, or missing something obvious.

{% for thisCategory in entry.eventType %}

    <h1>Other Events in {{ thisCategory.title }}</h1>
    {% set category = craft.categories.slug(thisCategory.title) %}
    {% set entries = craft.entries.section('events').relatedTo(category).find() %}

    {# If there are any entries, loop through them #}
    {% if entries | length %}
        {# For each entry we find, do this #}
        {% for entry in entries %}
            <p>{{ entry.title }}</p>
        {% endfor %}
    {% else %}
        <p>Found no entries</p>
    {% endif %}
{% endfor %}

Answer 1

Your approach seems interesting but you should never do such "relations". They can be broken all over the way. Let me explain that.

Title vs Handle

Most objects in Craft have the attributes title and handle. The title is the name that can be rendered in the frontend. This should be your attribute to show users what the object is about. The handle is your "developing" attribute. This is a unique field, with several validation rules to make this field selectable via getEntryByHandle() thus you can link entries via handle, get them via handle and change the display name (title) however you like and can still select those via handle.

<h1>Other Events in {{ thisCategory.title }}</h1>

Is totally correct, you show the title to the frontend

{% set category = craft.categories.slug(thisCategory.title) %}

Is absolutely wrong. The validation rules for title and the validation rules for the slug attribute are totally different and you should never match those fields. When you have a title like Foo Bar you'll never be able to match them since your slug would be foo-bar.

The correct way would be this

{% set category = entry.yourCategoryFieldHandle.first() %}
{% set entries = craft.entries.section('events').relatedTo(category).find() %}

If you really really want to relate objects not via the relation Field but via strings you should do it with the handle but never with titles or slugs