Unless it causes a problem to have Playing Track info show up in both the bottom panel and tabs, I think the show/hide button for the panel should be permanent just like the left, right, and library explorer buttons. I keep getting confused when it goes away, and I *know* how to get it back. At least maybe it could start available like the other buttons, and be hidden if that section is moved to a tab?
Edit: Okay, now I've discovered that there is a very obscure way to make the left panel button disappear, via context menu. Maybe that should be taken out, too?
Edit again: Tangential, but equally problematic. Having switched the right sidebar into a floating window, there's no clear way to send it back to the right sidebar. *facepalm* Of course the X button does it. Was so used to arrows and right click menus that I missed the obvious.
On the other hand, the floating window doesn't seem to keep the same components as the sidebar. Lyrics become hidden, and now playing list shows up even if the reverse is true in the sidebar.