I built a template that has a data set property on it, and everything was working great until I needed to add a new column to the template data set and that column did not propagate to all of the instances of the template. Is there a way to fix this?
If you added the new column to your dataset on the original template, and not an instantiation of that template, this should propagate correctly. I would double check that you edited the template definition.
Where is your template created? Global < Templates? Or Project < Templates?
8.0 doesn’t have global templates, but I did verify that I made the change to the actual template and not an instantiation of the template.
This isn’t a great workaround, but for the sake of clarification - if you delete the existing instance of the template and create a new one, I assume it gets the correct value for the dataset?
We probably aren’t “diffing” the actual dataset in the template master (in part, because we expect them to be overriden) and also in part because diffing datasets is expensive. If you can confirm the behavior on a new template instance, I’d say it’s “working as intended”, although a case could be made for changing that behavior (ideas.inductiveautomation.com 
)
That is correct. New instances of the template will have the dataset from the template. If that is the way it is supposed to work then I’ll probably just use a bunch of properties rather than a dataset of properties since those will propagate down to the instances of the template.