Maybe this is intentional, but it looks like the sliding box has a transparent background and when it is floating over something then it can be difficult to read the box.
I've seen it using FF 184.108.40.206 and IE7 on Vista.
Thanks for the comment. We've been improving that box quite a bit and you should see the new/improved version in the next week or so. It should address the issue you mention, plus you'll be able to resize it yourself and tell it to stop sliding up and down your browser.
Please keep the feedback coming, it's really appreciated.