Make the categories collapsible

opentech/public/projects/models.py

@@ -10,6 +10,7 @@ from modelcluster.fields import ParentalKey
 from wagtail.wagtailadmin.edit_handlers import (
     FieldPanel,
     InlinePanel,
+    MultiFieldPanel,
     PageChooserPanel,
     StreamFieldPanel,
 )
@@ -124,7 +125,11 @@ class ProjectPage(FundingMixin, BasePage):
         InlinePanel('contact_details', label="Contact Details"),
         InlinePanel('related_pages', label="Related Projects"),
     ] + FundingMixin.content_panels + [
-        FieldPanel('categories', widget=CategoriesWidget),
+        MultiFieldPanel(
+            [FieldPanel('categories', widget=CategoriesWidget)],
+            heading="Categories",
+            classname="collapsible collapsed",
+        ),
     ]
 
     def category_options(self):

opentech/public/projects/templates/projects/widgets/options_widget.html

 <li>
-<h2>{{ widget.attrs.label_tag }}</h2>
+<h1>{{ widget.attrs.label_tag }}</h1>
 <fieldset>
 {% with id=widget.attrs.id %}
 <ul{% if id %} id="{{ id }}"{% endif %}class="fields {% if widget.attrs.class %}{{ widget.attrs.class }}{% endif %}">{% for group, options, index in widget.optgroups %}