When pinning an image from the web, the Pinterest bookmarklet scrolls through the images on the page, like this http://screencast.com/t/xvqtsu9o3Sk

Mine doesn't scroll, so it doesn't all the user to select any image on the page. See this http://screencast.com/t/GvdoPhhb7h
(You might need to move to the right to see how the page does not move up or down.)

Do you have any idea why it doesn't scroll?

Thanks a lot