Message Tray/Panel in Fedora 19 Schroedigners Cat is not visible by pressing the Meta/Windows-Key

Fedora 19 doesn't show the Message Tray/Panel when you press the Meta/Windows-Key.

You can press <Alt>-<Ctrl>-<TAB> to get a switching window for selecting Desktop sections:



The Message Tray shows the panel, where e.g skype is visible after beeing minimized.

UPDATE : after installing CoverflowAltTab, the keys do not work anymore.
But with <Meta/Windows>-<m>, the message try is displayed.