Problem raised for earlier versions and marked as fixed ( http://tracker.moodle.org/browse/MDL-27169 ) has reappeared in past week for Moodle 2.3. Users are just getting the spinning icon in the content section but the input box to select a file never appears. See forum discussion - it's been raise by people at 3 institutions. https://moodle.org/mod/forum/discuss.php?d=206599

Thanks, Gordon.