Some Mac users have noticed that they are unable to see the scroll bar in the Grade Center. This issue isn't really a Blackboard issue, but rather a conflict with the way OS X handles scroll bars in general.  Fortunately, there is an easy fix.

Launch System Preferences, either from the Dock or from the Apple menu. 

Click the General button. 

This will bring you to the General settings. In the Show scroll bars section, select Always.  

Close the window to save your changes.

The scroll bar will now always be visible, even when you're not scrolling.