I found out the hard way that if you like to display your emails sorted by 'unread, descending' in a threaded format, it hides unread emails! This is really bad and should be fixed, as it caused me to miss many emails. The threaded group needs to show that it contains unread emails by being bolded, just as single emails are. I am aware I could set it to show in unthreaded format, but I would prefer threaded, if it didn't have this problem. To me, this is a bug, so I would request that it gets addressed. Thank you!