Alley Cat,
If you single click on an aircraft in the Network list, the map will not jump to that aircraft unless you double click on it.
If you select an aircraft then click the "Pan Map with aircraft" button, that aircraft is marked for tracking and the map will jump back to this aircraft next time its position is updated.
I've just tested this, selected a "live" aircraft, clicked the "Pan Map..." button, gone to the Network list and double clicked on an aircraft - the map centres on this aircraft - then as my live flight set to "Pan Map" with updates, the map goes back to this aircraft. This is what I would expect to happen.
So, as tarbat said, you probably had the "Pan Map with Active Flight" button selected and it was doing just what you asked :-)