Doesn't look like you upgraded properly then as you still have the older version of the javascript file that we replaced in 1.6.3 to fix this issue
Upload the 1.6.3 files again, or better yet, upgrade to 1.6.4, which involves replacing all files anyway.
Thanks for looking into this for me Matt. I find the upgrade process rather daunting as I am always convinced I will lose something in the process but I guess I will have to bite the bullet and move up to 1.6.4 now...
Just make sure to backup your database (just incase) and you should be fine.
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If you have full database and file backups, even if the upgrade goes catastrophically wrong (which is extremely unlikely) you can just restore it. Make sure the new files overwrite the old ones, that's what didn't seem to happen when you upgraded to 1.6.3.