If the DF Preview pane is open and you press the Windows key to open the Start Menu, and then you press another key to search (and migrate the Start Menu to the second monitor ), the preview pane covers up the Start Menu and you can't see it.

Windows 7 taskbar closes the preview pane when the Windows key is pressed, or when any key is pressed - other keys just go to the focused window.

FYI, a slight difference occurs in Beta 9 - when I put the mouse cursor over an icon to bring up the preview pane (?) then press the Windows key, the DF Start Menu opens on top of the preview pane, then the preview pane redraws a second later on top of the Start Menu.