First, it was Ubuntu which innovated in the scrollbars creating a nice overlay, but making them unusable for those like me using a track pointer or a mouse without wheel.
Now, with GTK-3.0, the scrollbars have also changed their default behavior and when clicking above or below, the scrollbar moves immediately to that position.
Again, this makes it unusable unless you have a wheel in your mouse or have another fancy way of scrolling, like a touch pad.
I’m nowadays a proud owner of a Lenovo X220 and I use the track pointer included disabling the annoying touch pad thanks to the Touchpad Indicator GNOME extension. I say “annoying” because, when using the track pointer, I tend to touch every now and the the touch pad with unpredictable results.
So, with the new behavior and without the possibility of scrolling with a mouse wheel or a touch pad, viewports with a long extension are really difficult to browse with the pointer. This is the case for several of my mail folders in Evolution. As a result, I was getting nuts.
Therefore, I wanted to go back to the old behavior. This is: when clicking above the bar it would mean “PgUp” and when clicking below “PgDown”.
Fortunately, GTK-3.0 provides a way of tuning this. You have to add an option to its “settings.ini” file. If you want to apply it system wide, you will do it in “/etc/gtk-3.0/settings.ini” while if you want only to affect an user, you will do it in “~/.config/gtk-3.0/settings.ini”.
This is how it looks like:
Hope this helps to someone else!