diff --git a/indico/web/templates/forms/category_picker_widget.html b/indico/web/templates/forms/category_picker_widget.html
index e7cdb0a2b36..078edc5ed97 100644
--- a/indico/web/templates/forms/category_picker_widget.html
+++ b/indico/web/templates/forms/category_picker_widget.html
@@ -13,7 +13,8 @@
                 {% endtrans %}
             {% endcall %}
         </div>
-        <button class="i-button" 
+        <button type="button"
+                class="i-button"
                 id="categorynav-button-{{ field.id }}"
                 data-title='{% trans %}Choose category{% endtrans %}'>
             {%- trans %}Choose category{% endtrans -%}