Yesterday I upgraded our Orion server from 10.1.1 to 10.1.3, after which I noticed that the AJAX resources were not loading. It's not that the Ajax part doesn't load, the entire resource including headers is not there. I have edited views to move, delete, and add the AJAX tree resource with no change - it never shows up. I have run the config wizard again also with no change. I have opened a case with Support.
Aaron