Verticle Sharebar Jumping

Hello,

I was hoping someone could help me fix the sharebar on my site (example page: http://www.livefreedietravelling.com/travel/job-seeking-in-perth/).

It’s installed and working well, but when I scroll down, just before the top of the page reaches the top of the sharebar the sharebar jumps up like a magnet and then continues to function as normal.

From other sites I’ve seen this is not normal behaviour.

Any help would be greatly appreciated,

Regards,
Paul

http://wordpress.org/extend/plugins/sharebar/