Disabling in-app notifications breaks quick-search

If you set the in-app notifications to be disabled by selecting "does not provide in-app notifications" on the configuration page: http://localhost:1990/confluence/plugins/servlet/myworkserviceselector.action of a clean confluence install (atlas-run-standalone --product confluence --version 5.3.1)

Then, when you attempt to use the quick-search functionality, you just get a spinner showing and no drop-down area appears.