Auto-running Through Combo Box

When a Combo Box is first opened, the vertical slider doesn't quite sync up with the contents. The slider will move up and down, but the contents of the combo box won't automatically slide up and down with that slider until the slider has first gone to the bottom of the list.

I've sat here for 10 minutes and waited -- no difference. Unless I physically slide the slider all the way to the bottom of the list, the contents of the combo box will not slide with that slider.

How can I make the contents sync up with the slider right away so that I can more easily find things 1/3 of the way down without sliding the bar all the way to the bottom to sync it up then back up to slowly slide the slider until I see it?