April 25, 2013, 4:45 PM — Here's how you can disable overlay scrollbars in Ubuntu 13.04.
1. Open a terminal window.
2. Type in the following command then hit Enter.
gsettings set com.canonical.desktop.interface scrollbar-mode normal
3. To get overlay scrollbars back, use this command.
gsettings reset com.canonical.desktop.interface scrollbar-mode
For more, see the original article at the link below.