Middle-click and drag doesn't trigger "scrollball"

Middle-click and drag doesn't trigger "scrollball"

I've just came from a Windows system (in fact, I'm dual booting Ubuntu
12.04 and Win7), and in my Firefox installation back then, when I pressed
the middle mouse button (mouse wheel), it displayed a circle that I could
move the pointer away from to navigate around the page in a 2-dimensional
scrolling. In Ubuntu's Firefox, I don't see this behaviour. Is there a way
to enable this feature? I beleive it would require a different version of
Firefox, because when I search middle in about:config, ot only has
middlemouse.scrollbarPosition;true
middlemouse.paste;true
middlemouse.openNewWindow;true
middlemouse.contentLoadURL
browser.tabs.opentabfor.middleclick;true
I'm using the canonical release 23.0, by the way.