Users of Mac computers might notice that the scrollbars disappear in their web browsers after a few seconds of inactivity. Follow these steps to learn how to disable the automatic disappearing scrollbar setting for Mac computers.
From the Apple menu, select System Settings.
Click Appearance. The following screen displays.
Set the Show Scroll Bars setting to Always.
Close System Settings.
Once you close the screen, all changes are saved and scroll bars will no longer disappear.