Try Help/Restart with Add-ons disabled (safe mode) to see if there's a broken layout. Any difference? The arrows are working here with 68.2.2/W10.

Thanks for the suggestion, but no, Safe-Mode makes no difference. BTW, I am running TB 68.2.1 under Linux Mint 19.1 .

And my ~/.config/gtk-3.0/gtk.css has:

.scrollbar,  scrollbar {
   -GtkScrollbar-has-backward-stepper: true;
   -GtkScrollbar-has-secondary-forward-stepper: true;

}

I love Thunderbird. Totally. But the lack of arrows on my vertical scrollbar to navigate my emails is driving me crazy. Using the scroll ball on my mouse does not work the same. I've looked all through Mozilla support as well as MozillaZine support forums and can't find a fix.

Firefox is fine on this system — its scrollbars are just dandy — as per usual.

Thunderbird isn't, because of this singular, seemingly innocuous, yet completely annoying issue (but trust me, I love Mozilla products!)

PLEASE HELP!

I'm on a Mac, OS 10.11.6

THANK YOU!