I am thinking I can't be the first person interested in this functionality and wonder if anyone has come up with a good work around.
I have a stakeholder that would like to be able to sum together multiple fields to compare amounts on a feature by feature basis. So for example, they want to know how many apple, oranges and bananas are sold at each store. Or maybe want to know just apples and oranges. It would be sort of an iterative question.
So far the best solution I can determine is creating an attribute field for this with arcade, however there are many (30-40) amounts they are interested in, so it would be great if they could temporarily calculate this (as sort of an extended Sum widget. Any suggestions appreciated.