A/C Fan runs when furnace is turned on

I'm not sure what my wife did but now when I hit thermostat 3 times to run the furnace, the roof air fan runs. The furnace does come on and responds to the thermostat setting but the only way to turn the roof fan off is to turn the thermostat off or turn off circuit breaker #4 (Roof A/C).
It must be a control system failure of some sort, any ideas of what to check further or how to go back to normal?

If your system is the same as ours, there are three settings for the fan: Lo, High and Auto. Set the fan to "auto" THEN turn on the furnace. This also makes it so the fan only runs when heat is needed with the heat strip instead of all the time. Took us a while to figure that out.

keelhauler, here’s your solution.  We had the same problem which was that the fan was set to ON rather than to AUTO. Click the button for the fan (first click), then change the fan setting to AUTO. Should work fine. If you use the AC and the fan is set to ON, the fan will run continuously, but will go on and off with the AC if the fan is set to AUTO.

Thanks to both of you. It seems that my wife just started hitting buttons then I was left with wondering why it didn't work. Works like a champ now.

It's good to have a wife that pushes your buttons. Especially when it's the right ones...  

Just by chance the same thing happened to us this past weekend. Don't know how we avoided it last winter. Of course it's always the wife's fault (and actually, I think I was the one who did it). We spent a chilly 35° night but luckily do have a small space heater. When all else fails, read the manual! We discovered "the fan on Auto and then select furnace" and it worked. Hurray! 
Marilyn & Paul