It seems that when in Workspace Switcher view, the alt-tab menu isn't directing you to an application when selected and the Workspace Switcher is not completely deactivated.
* open up multiple windows
* open the Workspace Switcher
* open alt-tab menu
* see that navigating through the alt-tab menu with the arrow keys, navigates through the workspaces as well
* also: selection of an entry in the alt-tab menu doesn't take you out of the Workspace Switcher
Using 4.24.0 in Oneiric
It seems that when in Workspace Switcher view, the alt-tab menu isn't directing you to an application when selected and the Workspace Switcher is not completely deactivated.
* open up multiple windows
* open the Workspace Switcher
* open alt-tab menu
* see that navigating through the alt-tab menu with the arrow keys, navigates through the workspaces as well
* also: selection of an entry in the alt-tab menu doesn't take you out of the Workspace Switcher