This worked fine in 11.10, but today I upgraded to 12.10 and I can't remember what I had to do to get this to work correctly. What I want is:
When in a workspace, the only icons in the taskbar should be for applications that are running in the current workspace. What I see now are all application icons regardless of the workspace they are running in.
I am using Gnome Classic since I have a VPN client that only shows it's status in the system tray from Gnome Classic.