Compound query conditions
We allow grouping of semantic query conditions, but not in the web UI. Adding grouping makes the UI much more complicated, but allows exact query authoring. We've taken a simpler approach that is largely based on browsing and drilling down iteratively after applying a set of conditions (thereby making an implicit intersection of the criteria and their results).
This is a place-holder bug to track whether we need to support super-expressive compound grouping.