Allow multiple category selection in listing and datasource webparts
When using a repeater webpart for instance you can only select 1 category. Same is true if you use a documents datasource or a hierarchical viewer webpart. The API allows you to pass in multiple categories when doing a document or object query but we do not have this same ability to do so with any of the out of the box controls.
I come across this use case in roughly every other site build. Unfortunately, it isn't available so we end up performing a no-so-fantastic work around by using the API to get what is needed vs. using OOTB tools.
Bryan Johnson commented
We've had to build custom web parts to provide this behavior. It would be great to have this as a standard feature.