Why do snapshots need to be from reports of the same theme?

In order to compare data, snapshots need to be from reports of the same theme. This is designed on purpose to avoid errors and confusion, especially when grouping snapshots.

Different themes can have different fields, and different fields can have different meanings. For example, a field called "Type" might represent a different type of data in two different themes.

Keep this in mind when building widgets comparing data from themes with similar names, such as "Orders" and "Order Lines," or "Location," "Location Content," and "Location Content Breakdown." Though there's some crossover, these themes have different fields, and the data they represent is not compatible.