All of a sudden, I found I could no longer use the two-finger up/down gesture to move up/down a web page in Chrome. Seemed to work in other apps, however. Found the 'work-around' was to disable the "Swipe between pages" function in the System Prefs->Trackpad->More Gestures checkbox setting. Disable that setting, restart Chrome/FF, vertical scrolling now works and does not break even if you try to move back/forward between web pages. Not purfekt, but I seldom use the back/forward swipe, actually, it's more often been accidental than desired! Just add a little horizontal movement to the up/down swipe and the trackpad seems to 'think' I really wanted a back/forward rather than a vertical scroll.
And there's still the command-left/right arrow method...
Now I can hide the Trackpad Pref panel, again. WOW! I actually didn't have to do anything! System Prefs 'remembered' my Customised settings. All I had to do was quit System Prefs or just return to the 'Show All' screen!