What are overlay scrollbars?
Ubuntu includes overlay scrollbars which take up less screenspace than traditional scrollbars, giving you more room for your content. While inspired by mobile devices where traditional scrollbars aren't needed, Ubuntu's overlay scrollbars are designed to work just as well with a mouse.
Some apps like Firefox and LibreOffice don't support the new scrollbars yet.
Use the scrollbars
The overlay scrollbar appears as a thin orange strip at the edge of a scrollable area. The position of the scrollbar corresponds with your screen's position in the scrollable content. The strip length corresponds with the content length; the shorter the strip, the longer the content.
Move your mouse pointer over any point on the scrollable edge of the content to reveal the thumb slider.
Ways to use the scrollbars:
Click the top half of the thumb slider to scroll one page up. Click the bottom half to scroll one page down.
Drag the thumb slider up or down to move the screen's position exactly where you want it.
thumb slider to move the screen's position without needing to drag or scroll page by page. This is especially useful in long documents.on the
Disable the scrollbars
You can disable the new scrollbars if you prefer the traditional style:
Open the Terminal by pressing Ctrl+Alt+t or by searching for terminal in the dash.
Type the following command and press Enter:
gsettings set org.gnome.desktop.interface ubuntu-overlay-scrollbars false
and log back in for the change to take effect.
If you change your mind and want to re-enable the scrollbars, run this command:
gsettings reset org.gnome.desktop.interface ubuntu-overlay-scrollbars
Setting your theme towill also disable the overlay scrollbars.