I found a small work around for my previous post but i have no clue on how to do it.
"It appeared impossible to get rid of the default border lines of a select box by changing the css. A { border: 0; } doesn't work.
My workaround is to cover these border lines with 4 images around. Because the select box has to be clickable, it is impossible to realize it with one covering image with a transparent inside!"
Cover border lines of drop down with images
Threaded Mode