Why are the facet counts for categories and flagged documents all showing 0 in the sentiment view?
This is working as designed. In sentiment view, positive, negative, and ambivalent facet counts represent analyzed document count.
For instance, if a facet appears in positive view more than negative view, then the facet of the document is categorized to positive and counted as positive document. However, flag facets are calculated and counted dynamically at runtime. And flags don't appear in any view. So they are categorized to neutral and it shows "0" as designed. The same is true for categories.