When I use the hotkey for Contents (Ctrl+Shift+C), it switches between opening Favorites and Contents. More specifically, it opens whichever tool I opened last.
If I manually open Favorites from the secondary toolbar, Ctrl+Shift+C will open Favorites next time I use it. If I then open Contents from the secondary toolbar, Ctrl+Shift+C will open Contents. Of course I'd be happy for Favorites to have a hotkey assigned to it, but it should be different from the one assigned to Contents. Mixing the two is inconvenient and causes confusion.