Gauges disappear when FS9 unpauses

On a number of panels to which I have tried to add simple gauges (like an Avionics on/off switch), they added gauge is visible when the sim starts (paused) but as soon as I unpause it the gauge disappears. It is still there and the little 'hand' cursor is visible when you hover the mouse over it, but the gauge itself is invisible. If I reload the a/c paused, the same thing happens - the gauge is visible until I upnpause the flight, then it goes.What causes this and how can I prevent the gauge from becoming invisible like this?Thanks,Martin