by Nancy K Hoke.
Dear Stephen - I can provide a little insight into your problem. We found when we upgraded to Moodle 2.3 that several elements of Moodle were not functioning in IE. This was especially true for the drag and drop files. Once faculty switched to FireFox the problem was solved. We did switch from Windows server to Linux. We also found in Moodle 2.3 that with IE with editing turned on not all of the edit icons would display. I hope that this may be of some help.
Nancy K.