I wonder if it has anything to do with the HiDPI issue: https://bugzilla.mozilla.org/show_bug.cgi?format=default&id=1404042 https://bugzilla.mozilla.org/show_b

I wonder if it has anything to do with the HiDPI issue: https://bugzilla.mozilla.org/show_bug.cgi?format=default&id=1404042 https://bugzilla.mozilla.org/show_bug.cgi?format=default&id=... (there's a couple of hits when I search for 'scrolling' in that thread)