I currently have an FMS15 dev server, to test a number of different solutions, prior to upgrade. Most have a single-file architecture and a few of those include a WD interface. The dev server does not have a SSL certificate installed and it only has (so far as I know), the single test connection. I have no problems with the single-file WD solutions - BUT - I'm having 'log out messiness' with the one, three-file solution, that also includes a WD interface.
Basically, I get three messages (ie one message, three times) at WD log out. It has the heading, "Error", then "Your access privileges do not allow you to perform this action." Superficially, it's extremely clear but I've checked and rechecked and I can't see any of the obvious priv-related errors. That also made me wonder about a 'single test connection', with regards to a three-file solution... I'm pleased that it 'works', but perhaps the multiple files are triggering the logout error(s)?