When the mouse is over the control, I'd like to be able to select (ie set selected=true) the option it's hovering over.
In other words, I'd like it to work exactly the same way the list portion of a dropdown (single item SELECT) works.
Figuring out which item the mouse is over is fairly straightforward.
-> I'm having a problem figuring out the index of the topmost visible option.
ie, if the example SELECT was scrolled to the bottom, the index of the topmost visible item is 1. I can't seem to find a property of the SELECT or OPTION that enables me to determine this.