How to arrange all inboxes from multiple accounts on top of the sidebar.

I used to be able to list the inboxes of 5 accounts at the top of sidebar and then the standard listing of each account with folders below. (I used to be able to slide the boxes up to this section. If I remember there was a line between the sections. This allowed me to see whenever there were new items in any inbox without scrolling the sidebar through hundreds of folders. But it also allowed me to have the folders available as well. I can have them listed at the top if I identify all the inboxes as favorites and select favorites to show but I lose the rest. I have lost the ability to set things up this way. It's been frustrating enough that I've started looking for another email client.