[xmonad] XMonad 0.10 only matches on last className?

If I run xprop on my emacs I see this: WM_CLASS(STRING) = "emacs", "Emacs23" If I setup a keybinding to runOrRaise looking for "emacs", it always starts a new instance: , ((modMask, xK_w), runOrRaiseNext editor (className =? "emacs")) If I change it to match on Emacs23, then I get the expected runOrRaise behavior: , ((modMask, xK_w), runOrRaiseNext editor (className =? "Emacs23")) Is this a bug, or is there a different syntax I'm supposed to use for when I want to match on any of the WM_CLASS's that the window has specified?