Ubuntu – How should I handle multiple monitors when I regularly connect and disconnect different monitors and projectors

I'm moving from a macbook pro (with MacOSX) to a lenovo T430 running ubuntu 12.10. I use the laptop for work, and work from home regularly. I have an external 30" monitor at home, an external 23" monitor at work, and often need to connect my laptop to projectors.

I've found so far with Ubuntu that connecting an external monitor or projector seems to do the right thing (i.e. extends the desktop to display on the monitor/projector), but when I disconnect the monitor, it leaves the 'workspace' the same size as it was when the external monitor was connected – so I can't see any windows that were on the external monitor. If I go into "Workspace Switcher", I can see the windows and drag them onto the laptop monitor to work with them.

if I go to 'System Settings -> Display' and detect displays, it seems like the workspace size gets fixed, but instead of having all of my windows on my workspace on my laptop display, they get spread over other workspaces, so I still have to go into "Workspace Switcher" and drag windows around.

I'm really hoping there's a way to get similar behaviour to MacOSX, which automatically resizes the workspace when the monitor is removed and moves all windows onto your screen so they are visible.

Any advice or ways to make this less painful?

Update on Feb 11, 2013: I've been retesting this, and it seems like the workspace size is now being updated automatically when I disconnect/reconnect the monitor cable. I don't believe I've changed anything, so not sure why I'm seeing different behaviour here.

The second part of the problem – moving all windows onto the main workspace – still exists