Can't unselect parent from admin panel

[Ryan J Ollos]

When editing a component from the admin panel, I don't see a way to select no parent. The following change would seem to fix the issue:

componenthierarchy/admin.py

@@ -137 +137 @@
 
             select = tag.select(id='parent_component',
                                 name='parent_component')
+            select.append(tag.option('', value=''))
             for comp in sorted(all_components):
                 if comp != component and \
                         not self._ChModel.is_child(component, comp):

[Ryan J Ollos]

In 16091:

0.2: Allow Parent Component to be removed

Fixes #12992.