diff --git a/tests/admin_pages/test_datasource.py b/tests/admin_pages/test_datasource.py
index c9535c65d..43a00561c 100644
--- a/tests/admin_pages/test_datasource.py
+++ b/tests/admin_pages/test_datasource.py
@@ -375,6 +375,22 @@ def test_data_sources_view(pub):
     CardDef.wipe()
 
 
+def test_data_sources_agenda_view(pub):
+    create_superuser(pub)
+    NamedDataSource.wipe()
+
+    data_source = NamedDataSource(name='foobar')
+    data_source.data_source = {'type': 'json', 'value': 'http://some.url'}
+    data_source.external = 'agenda'
+    data_source.store()
+
+    app = login(get_app(pub))
+    resp = app.get('/backoffice/settings/data-sources/%s/' % data_source.id)
+    assert 'This data source is readonly.' in resp
+    assert '/backoffice/settings/data-sources/%s/edit' % data_source.id not in resp
+    assert '/backoffice/settings/data-sources/%s/delete' % data_source.id not in resp
+
+
 def test_data_sources_edit(pub):
     create_superuser(pub)
     NamedDataSource.wipe()
diff --git a/wcs/admin/data_sources.py b/wcs/admin/data_sources.py
index a2e6eb237..5046f3975 100644
--- a/wcs/admin/data_sources.py
+++ b/wcs/admin/data_sources.py
@@ -233,6 +233,8 @@ class NamedDataSourcePage(Directory):
             self.datasource = instance or NamedDataSource.get(component)
         except KeyError:
             raise errors.TraversalError()
+        if self.datasource.external == 'agenda':
+            self.datasource.readonly = True
         self.datasource_ui = NamedDataSourceUI(self.datasource)
         get_response().breadcrumb.append((component + '/', self.datasource.name))
         self.snapshots_dir = SnapshotsDirectory(self.datasource)
@@ -241,7 +243,8 @@ class NamedDataSourcePage(Directory):
         r = TemplateIO(html=True)
         if self.datasource.is_readonly():
             r += htmltext('<div class="infonotice"><p>%s</p></div>') % _('This data source is readonly.')
-            r += utils.snapshot_info_block(snapshot=self.datasource.snapshot_object)
+            if hasattr(self.datasource, 'snapshot_object'):
+                r += utils.snapshot_info_block(snapshot=self.datasource.snapshot_object)
         r += htmltext('<ul id="sidebar-actions">')
         if not self.datasource.is_readonly():
             r += htmltext('<li><a href="delete" rel="popup">%s</a></li>') % _('Delete')