I don't use dashboards a ton, but I have run into this on two projects now, so I thought I would share as a request. In this one, I have two maps that are almost identical stacked on top of each other so that only one may be visible by the user at a time. Configuring my pie chart to filter based on selection is relatively easy for the first map, but on subsequent instances, the "enable same data source" feature goes away despite the layer being the same.
Example, map 1:

Map 2:

(Yes I am exposing myself as a horrible element namer!)
So, this is because the pie charts are only able to listen to one instance of the layer even though only one is visible at a time anyway. It seems I'd have to create a second set of charts and get them in there somehow. I poked around in AGO assistant but nothing jumped out at me as "easy." I may end up just creating a second dashboard and nesting them into at third dashboard, but it would be nice in cases like this to more easily set up the same charts.