Comment 4 for bug 1439615

> It's on desktop. You can currently press the red close button on the
> dash window to cause it to respawn. Button probably should be inactive,
> but wallpaper shouldn't go away either :)

yup, the problem is that the background turns black. I guess it is because something wrong in Desktopstage.qml, maybe ApplicationWindow.qml, because the ApplicationManager gets nothing when no application is running.