Middle-click
Many mice and some touchpads have a middle mouse button. On a mouse with a scroll wheel, you can usually press directly down on the scroll wheel to middle-click. If you don’t have a middle mouse button, you can press the left and right mouse buttons at the same time to middle-click.
On touchpads that support multi-finger taps, you can tap with three fingers at once to middle-click. You have to enable tap clicking in the touchpad settings for this to work.
Many applications use middle-click for advanced click shortcuts.
In applications with scrollbars, left-clicking in the empty space of the bar moves the scroll position directly to that place. Middle-clicking moves up to a single page towards that location.
On the desktop, you can quickly open a new window for an application with middle-click. Simply middle-click on the application’s icon. The applications overview is displayed using the grid button in the dash.
Most web browsers allow you to open links in tabs quickly with the middle mouse button. Just click any link with your middle mouse button, and it will open in a new tab.
In the file manager, middle-click serves two roles. If you middle-click a folder, it will open in a new tab. This mimics the behavior of popular web browsers. If you middle-click a file, it will open the file, just as if you had double-clicked.
Some specialized applications allow you to use the middle mouse button for other functions. Search your application’s help for middle-click or middle mouse button.