I noticed that when selecting canned responses in Internet Explorer it didn't work. It works fine in Firefox. (my preferred browser but not the choice of my co workers)
Upon investigation I found that the ajax.js is pretty old. Luckily there is a http wrapper update which works and can be found here.
http://adamv.com/dev/javascript/files/request.js
Just replace the code in ajax.js found in /scp/js/ajax.js with the code found at the link above. It's just a cut and paste job, be sure to just close the current code /*old code*/ and paste in the new and test prior to removing the old code entirely.
Or insert the copy of my ajax.js which is attached you will need to convert this txt file to .js and name it ajax.js.
I hope this helps anyone else who has found this bug.