Thanks for the details Jason.
Yes - those sites I was testing has the stand alone version of HTML Editor so I updated them to use the version from Data Bridge instead. It is working fine now.
However - KFM still does not work (as you mentioned it wouldn't). Using the developer tools to make the change won't work either, as KFM opens in a new window which always defaults to IE10. The program will stop responding, so at that point there is not way to recover or change anything. Unless there is a way to make that change stick as the default it won't do much good.
I know KFM is not a well maintained project, but I sure hope a fix is available soon for that. For now I'll have to tell my clients they have no choice but to use Firefox or Chrome for editing sites.