For those concern with memory leaks (unjustified - high memory usage) there is an add-on that helps a lot with this matter: https://addons.mozilla.org/en-US/fir...on/memory-fox/ - would have been nice if this was integrated as a feature, at least until they find a fix at core of the problem.

PS.After install you need to activate it - right click on Icon -> "Activate Memory Fox - Browser Only"