What's Status of Desktop Search in KDE? Is Search of Kmail Messages Working Yet?

Anyone know that status of desktop search in KDE on 16.04? What's working and what is not?

I've been ruing Kubuntu 16.04. It's good. However, a search via Kruer does not retu Kmail messages. For a very long time, this was a known problem. It's my impression that it's been fixed. Has it? Displaying Folder_Properties->Maintenance in Kmail shows full text indexing is enabled, but the status remains "Still Not Indexed". I've restarted the indexer several times.

Also, "balooctl status", which retus "the status of the indexer", shows this:

Finally, is searching Kmail messages a "Plasma Search" function or is it a "File Search" function? Those are the alteatives displayed in System_Settings->Search. I've never found a lucid explanation of the differences and what does what. E.g., what does the "Terminate Applications" Plasma search plugin actually do? Does it index apps I have terminated and retu them in a Kruer search?

Or are those simply the various little functions Kruer provides, and really have noting at all to do with desktop indexing and searching?