Remember that the Firefox Browser caches the selected position on Select Boxes. I am not sure how to turn this feature off.
This means that if you select an option on a select box, and refresh, firefox will remember your select box index position. I've noticed the same behaviour on checkboxes and radio buttons, so be aware when debugging.
Heuristically speaking, I like the function, especially when filling out long involved forms. It is however, a complete pain in my MULE when I am debugging applications and can't figure out why the box isn't selected to the expected option.
Pressing CTRL+F5 redraws everything sans state.