Trying to use Scrollbar in selectbox container Hides container

[cubars]

Here's my example.I'm using a slightly modified version of the selectbox plugin. One of the modifications I've made is to add a class that restricts the height of the options container and adds a scrollbar when it would otherwise be more than 50% of the height of the nearest relatively positioned parent. But now when I try to click and drag the scrollbar in the container (particularly in IE and Chrome), the container disappears as if I've clicked outside of it.Is there a way to detect when the focus is on the scrollbar? Or is there any other modification to the plugin you could recommend that would keep the options from disappearing until one is selected or there really is a click event outside the container?