Here is my 2 cents worth.

Ubuntu+Unity+gnome-session-flashback+with Compiz+4 workspaces

1) Click on a workspace icon and the top and bottom panels disappear.
2) Wait for app indicator icons to appear. Click on workspace icon and top and bottom panels disappear. Open a utility - Ctrl+Alt+T (terminal) and top and bottom panels reappear. Click on app indicator icon and top and bottom panels disappear.
3) Wait for app indicator icons to appear. Click on app indicator icon - work as normal. Click on workspace icon and top and bottom panels disappear. See item 2.

Ctrl+Alt+arrow keys do not switch workspaces.

I have not tested this on with Metacity. I first need to work out how to increase the number of workspaces.

Regards.