Comment # 11 on bug 1053959 from Yunhe Guo

About the inactive window scrolling problem, my description to reproduce it:

1. Open Firefox window and another application window with scroll bar, like a
PDF reader.
2. When focus on Firefox window, you move mouse on the other application window
and scroll mouse wheel, PDF pages was scrolled.
3. When focus on the other window, you move mouse on Firefox window and scroll
mouse wheel, Firefox web page won't be scrolled. (But in official Mozilla
builds, it should do.)

When you use Firefox for a long time, may one or two hours, you will found
scroll bar suddenly doesn't work with mouse wheel but still work with touch
pad. This is the most annoying issue.

I can reproduce this on two different computers, both installed with openSUSE
Tumbleweed.