If I try to enter 'http://localhost:5000/internal/oauth' when registering a new applicaiton, it tells me it's an invalid URI for a web application. So, I change to internal, without touching the URI box. On trying to submit, nothing happens, since the form fails to submit due to the still-invalid URI. To make it work, I need to switch back to "Web Application", delete the bad URI, and then switch back to "Installed Application"