diff --git a/src/core/Resources/views/form/bootstrap_4_form_theme.html.twig b/src/core/Resources/views/form/bootstrap_4_form_theme.html.twig
index fd6f181..0ad8522 100644
--- a/src/core/Resources/views/form/bootstrap_4_form_theme.html.twig
+++ b/src/core/Resources/views/form/bootstrap_4_form_theme.html.twig
@@ -83,9 +83,11 @@
 {% endblock %}
 
 {% block murph_collection_widget %}
-    <div data-collection="collection-{{ collection_name }}" {{ block('widget_attributes') }}>
+    {{ dump(row_attr) }}
+    <div data-collection="collection-{{ collection_name }}" {% for attr, value in row_attr %}{{ attr }}="{{ value }}"{% endfor %}>
+        {% set attrs = attr|merge({class: 'mb-1 ' ~ (attr.class ?? '')}) %}
         {% for item in form %}
-            <div data-collection-item="{{ loop.index }}" class="mb-1">
+            <div data-collection-item="{{ loop.index }}" {% for attr, value in attrs %}{{ attr }}="{{ value }}"{% endfor %}>
                 {% for child in item %}
                     {{ form_row(child) }}
                 {% endfor %}