Mileage tracking style not chaning with car
 

I have 2 cars that I track, one by odometer reading, & one by miles since last fill up. My default car is tracked by odometer reading. When I switch to the other car, the field should switch to mileage since last fill up, but it doesn't. Currently I have to try to submit it with my mileage in the odometer reading field & when it fails, resubmit it with my mileage in the now updated mileage since last fill up field. For reference, I'm using Firefox 30.0 on a Windows 8.1 computer.