Menu bar on second monitor doesn't stick

Using Mountain Lion on a MacBook Pro 2008, with dual monitors and fast user switching, the menu bar doesn't stick where I put it.

Main user has menu bar on laptop monitor.

Secondary user logs in via fast-user switching, places menu bar on external monitor (that works) and logs out.

Main user logs back in from main login screen. Menu bar is (rightly) on laptop monitor.

Secondary user log in using fast user switching. In Lion, the menu bar would still be on the external monitor.

In MountainLion, the menu bar has popped from the external monitor to the laptop monitor. It doesn't stick.

Remedy anyone?