Ubuntu 12.04 : Middle Click Shortcut

Using Mouse:

1.  Usually Mouse has a scroll wheel, click it to use it as middle click.

2.  Some old mouse has middle click instead of scroll wheel.

Using Touch-pad:

1. On touchpads that support multi-finger taps, you can tap with three fingers at once to middle-click.

    Note: This feature is not available in all laptops. My laptop doesn't have this functionality.

THE SHORTCUTS 

1. "Paste Selected Text" inside applications. Select the text as normal, then bring your mouse(without deselecting) where you want to paste it, and finally use middle click to paste it. Some of the applications that I have tested till now are: gedit, chrome, terminal, gnote.

Note: Pasting text with your middle mouse button is completely separate from the normal clipboard. Selecting text does not copy it to your clipboard.

2. 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.

3. 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.

4. On "scrollbars and sliders", a regular click in the empty space moves by a set amount (such as one page) in the direction you clicked. You can also middle-click in the empty space to move to exactly the location you clicked.

References:

1. https://help.ubuntu.com/12.04/ubuntu-help/mouse-middleclick.html

2. https://help.ubuntu.com/12.04/ubuntu-help/mouse-touchpad-click.html