OK this is quick and simple:
When trying to edit the Version rules of either the Default channel or a new channel in an existing project, the Design Rule link DOES NOT WORK.
This is the error I am getting from the browser:
My project process consists of several NuGet packages, each of which is based on a custom step template based on the built-in Deploy a NuGet package step.
I really need to do this because, as you can see, I have a lot of packages to deploy and for each of them I need to ensure consistent treatment (run Pre- and Post- deployment scripts and carry out special Web config transforms.)
When I remove all steps from the Packages step(s) list in the Version rules edit section, and click on the Design Rule link, only then the Design Version Rule windows pops up.