Each optgroup a own ul? (Better styling)

[Rodeveer]

I couldn't find a option to break the optgroup into multiple ul list.
I created a "separateUL" option in my "local version". It works just fine. Maybe an idea to add a option there into the default options aswel?

$("select").multipleSelect({
separateUL: true,
});

[wenzhixin]

http://jsfiddle.net/wenyi/knbdm5hu/11/