Combobox border?!

I have tried changing all the styles associated with the combobox (borderColor, etc), and set borderStyle to none (which made the border go away around the dropdown menu) but I can’t for the life of me get the border that’s around the main part of the combobox to go away or change color. I skinned the button to get it to be red, but I just can’t figure out how to change that last detail. Any ideas? Thanks for any help.