Looking here I tried using Ctrl+Left-Click to open a link in a background tab. This works as expected, like when using the context menu item.

However, I'd prefer the mouse-only Middle Button click to do the same job as it's a bit more efficient and I'm used to doing it!

I've never had that happen with Firefox 4 on WinXP. I haven't updated my Netbook that runs Ubuntu to Firefox 4 yet.

1. Try disabling the Java Console 6.0.24 and the Java Quick Starter 1.0 extensions and see if that solves your middle-click problem.

2. Try the Firefox SafeMode.
A troubleshooting mode, which disables most Add-ons. (If you're not using it, switch to the Default Theme.)

1. You can open the Firefox 4.0 SafeMode by holding the Shft key when you use the Firefox desktop or Start menu shortcut.
2. Or use the Help menu item, click on Restart with Add-ons Disabled... while Firefox is running.
   

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before using the Firefox shortcut (without the Shft key) to open it again.

If it is good in the Firefox SafeMode, your problem is probably caused by an extension, and you need to figure out which one.
http://support.mozilla.com/en-US/kb/troubleshooting+extensions+and+themes

Thanks for your reply, edmeister.

I've tried Safe Mode on the XP machine this morning and the problem persists, I'll try it on the Ubuntu machine tonight but I suspect the result will be the same.

One other thing I've tried is to check the When I open a link in a new tab, switch to it immediately option. With this enabled the original page is not reloaded but, of course, I have to return to that tab from the new one.

We've just received a new Windows 7 PC in the office so I'll see if I can install Firefox 4.0 on that and see what happens there.

Thanks again.

Any specific page where that happens? I just tried that at Digg with an unmodified Profile in Firefox 4.0.1 and I can't duplicate that reloading of the "base page".

I've never had that happen using a middle-click on any version of Firefox, either on Windows or on Linux. I also haven't seen a difference whether it opens in the background (my usual preference) or a new tab open & switch immediately, but I don't use that setting very often and not since like Firefox 2 versions with any regularity. I can't recall any other users mentioning that difference in action between {Ctrl +Click} and Middle-click, either. Has me stumped as to why that is happening.

Stumped me too. Happens on all pages (that I've tried). Here's an example of the problem : http://www.youtube.com/watch?v=GAgZbA7i6X8

Having tried it on the Windows 7 machine and another XP machine it works OK on both so I'm guessing it's either something I've done/installed/changed or a botched upgrade from v3 with my particular mix of add-ons & extensions.

I'll try a fresh install of v4 this afternoon if I get a chance but failing that I'll just have to re-learn to use Ctrl-Click instead.

Thanks for your suggestions.

This is sooo annoying! It started happening to me at the beginning of August 2011. I'm using 3.6.18.

I've also noticed that :

( a ) it only happens once per new page load

( b ) if I do a dummy middle click on a blank area of a new page load before clicking an actual hyperlink the page doesn't skip to the top.

Nonetheless, neither are acceptable workarounds. Something has recently broken.

p.s. I have done the safe-mode test with all addons disabled. Makes no difference.

For me - the bug only ever occured on the google search listing which was rather annoying. Never happened in any other page?!

Nonetheless, it is related to Javascript in latest version of firefox 3.6.18. (I never had the problem before !)

If you disable Javascript the page doesn't jump with the middle click. But, again, that is not an acceptable solution..

I was having this problem and it was driving me nuts for days. I finally discovered that my scroll wheel button somehow got reset to a single click instead of a middle mouse click.