A middle-click with the mouse scroll wheel always opens the link in a new tab, there is no config possible. Whether you open the link in the background is controlled by "When you open a link in a new tab, switch to it immediately" in "Settings -> General -> Tabs".

Like you probably found, the behavior for a left-click is set via a pref on the about:config page. Normal links:

• browser.link.open_newwindow
  1:current tab; 2:new window; 3:new tab

JavaScript Links:

• browser.link.open_newwindow.restriction
  0:divert always; 1:divert never; 2:divert no features

No, i do not want to switch to the newly opened tab, i know that is in the basic settings.

When I middle mouse, it is opening a2nd tab, that is a copy of the tab i already have open. It is not opening the link itself.

I have left click as (1) for browser.link.open_newwindow. What I essentially need is middle mouse set to (3) for that. So the intended result will be, left click opens a link in the same tab, middle mouse will open in a new tab.

So the intended result will be, left click opens a link in the same tab, middle mouse will open in a new tab.

That is the default behavior. Does it still happen in Troubleshoot Mode?

When i first installed the default was, left click opened in a new tab and middle mouse did nothing. Im unsure why if what i want is supposed to be the default setup, I havent changed any setting previously, and i only just installed firefox on this PC. I was unaware of troubleshoot mode, but i will try that in the future.

I was able to find the config items i needed to get what I wanted,or get it back to default apparently.

Can you tell us what changes to had to change/undo to restore how this should work ?