Is there still no info on this problem? It's very annoying. I run WinXP SP3.

Make sure that you do not drag the tab down in the browser window while clicking on it.

You can drag that tab back to the tab bar in the original window to undo that detaching.

Drag Tab as Shortcut: https://addons.mozilla.org/firefox/addon/drag-tab-as-shortcut/

That's definitely not my problem (dragging). I'm sure it's a bug. Doesn't happen on my Windows 7 machine.

Dear exp0sure, I have the same problem too, and I thought I was the only one. It's very annoying! My machines: Windows 7 32 bits (office) and 64 bits (home). No solution?

Is there still no resolution for this? I re-installed FF, I even de-installed Touchpad & Mouse drivers but nothing helped. This tab/new window behaviour is utterly annoying to a point that Firefox is not an option anymore.

I have the same very annoying problem. When switching from one tab to another, it detaches itself and opens in a new window. This is a problem a friend of mine encounters too. And yes, we make sure the mouse is not press (not dragging) when moving the pointer off the tab. This is definitely a problem pertaining to version 4 and not with the previous version of Firefox.

We both use Firefox 4.1 (French) on a French version of Windows7

The only reason I stay with Firefox is because I use Web Developer intensively, a plug-in which is not as finished in Google Chrome (otherwise I would switch to it as this problem is driving me crazy).

However, I must say that the way your support forum works is just sterling !...