[xmonad] Configure eating of keys based on window class

Hi, would it be possible to configure xmonad to eat certain keys or key combinations to windows based on some predicate (window className) or globaly? I have tried to define this globaly by adding the following line to my keybindings: ((0, xK_Super_L), return ()) (As explained in https://mail.haskell.org/pipermail/xmonad/2012-February/012402.html) But this does not appear to work (key is still processed in the active window) Thanks a lot for any thoughts.