[No scrolling bar] on Apple developer library..

[internetlove]

Hello everyone. I have a macmini with mountain lion 10.8.4 and i use a logitech mouse with steermouse. In the first image as you can see there is the scrollbar as usually (at this address: https://developer.apple.com/library/ios/navigation/ ).But in the second image, when I go into one of the items on the left menu the scrollbar disappears. Anyone know if is it a javascript problem with the web page or an hardware/software issue? I have the same issue when i try to read the documentation via Xcode 4...any help is appreciated

First image:


Second image