Trying to compare revisions of a page that includes changes to a foreign key
field of a related model that declared a custom primary key failed with an
uncaught exception.
The root cause was ForeignObjectComparison filtering by the id field, which is
not present in models that declare a custom primary key.
The solution is simply to filter by pk instead of id, which always maps to the
primary key of the corresponding model.
Include a regression unit test.
- items longer then the page height are no longer broken by the submenu footer
- long lists of submenu items are no longer blocked by the footer (version number)
Other changes
- documents listing template - clean up white space
Documentation changes (editors manual)
- update images
- remove popular tags mention as this is no longer applicable
- add references to 'collection'
Resolves #2827
