Prevent Firefox from changing URL when middle-click

In Linux, highlighting text copies it, and middle-click of the mouse pastes that text.  Amazing functionality that the other OSes are missing for no good reason.

In Firefox on any platform, middle-clicking a link opens it in a new tab.  Too easy to not use this.

Firefox has the option of middle-clicking the mouse button to load a clipboard-copied URL in the current tab.  This is where the trouble begins.

I don't want the middle-click to paste my copied URL and change this tab, I want the middle-click to open the link in a new tab or to paste!  This is especially frustrating in Google Hangouts, where pasting a URL is common to share a link with your friends.  One pixel off, and rather than pasting, Firefox is changing your current tab.  Or a link, one pixel off and rather than opening a new tab to that link, it's changing the current tab to something on the clipboard.

Get it?  Yeah, kinda confusing.  Well, to fix it so that the middle-click never opens a randomly-copied URL, open Firefox and browse to 'about:config' (no quotes).  Filter for

• middlemouse.contentLoadURL

and set that to False by double-clicking.

Now, middle-clicking a link will open that in an new tab, and otherwise middle-clicking will paste the clipboard.  Never will your current tab be changed (by this middle-clicking).  Booya.