Has the Firefox memory leak returned?

In the past few weeks, I've seen evidence that the memory leak that has plagued Firefox in previous versions, appears to have returned. But it's returned only in localized conditions, which leads me to believe that not the browser, but a browser plug-in may be to blame.

Unfortunately, the one I'm suspecting right now is the latest Tab Mix Plus version 0.3.7.3, which we reviewed glowingly last October when it was first re-released for Firefox 3. On browsers where this add-on has not been installed, even when we open a slew of pages (and I am a heavy page consumer), I don't see evidence of the same leak. I'll keep you apprised as to what I find in later tests.