Have you tried making a new custom template?
Do the upgrades destroy/remove your new template?

I have upgraded the module a couple of times and my custom templates have persisted...

BTW, I can't say enough about the genius behind the  template editor  concept.

Sheer brilliance, that.

I had only modified the existing templates. I was in the belief that these templates were somehow private for each module instance or at least for each portal. Now i've learned, that they are somehow global for the whole DNN-installation.

I don't like the thought, that each portal admin sees all the templates, but OK, that's how it is.
I will now create custom templates, like you - so they should survive all updates to come.

Cheers,
Joe

Anyway: brilliant module!