Arch Linux

Which GTK3 theme are you using? Does it happen with Adwaita or other theme?

I use Zukitwo, though I just tried changing to Adwaita, and the issue is algo reproducible.
Here's my .config/gtk-3.0/settings.ini, though I don't think there'a anything relevant here:

[Settings]
gtk-application-prefer-dark-theme = true
gtk-theme-name = Zukitwo
gtk-fallback-icon-theme = gnome
gtk-icon-theme-name = elementary-xfce
gtk-font-name = Ubuntu 10

I can confirm it on full kde, and theme i use is oxygen-gtk{2,3}

gtk3 config ( if relavent )

[Settings]
gtk-theme-name = oxygen-gtk
gtk-fallback-icon-theme = gnome
# next option is applicable only if selected theme supports it
gtk-application-prefer-dark-theme = true
# set font name and dimension
gtk-font-name = Ubuntu 10
gtk-shell-shows-menubar = 1

@cybertorture - can you confirm the problem when using other themes too or just oxygen?

Aswaita and Industrial worked, seems like its not gtk3 after all. Thans for the tip, and cheers.

The same happens with Ambiance and Adwaita for me.

Even if the issue is not reproducible with some themes, I belive it's a GTK issue. Changing the theme (basically, a bunch of css files) shouldn't break scrolling in applications, no matter how buggy the theme.

Confirmed with oxygen-gtk3 only. Scrolling works in `oxygen-gtk-demo`, but not in `oxygen-gtk3-demo` after installing `kde-gtk-config` and changing settings in System Settings -> GTK.

Installing that package did shrink the mega large buttons in GTK programs such as Wireshark, but broke scrolling.

Editing ~/.config/gtk-3.0/settings.ini and commenting `gtk-theme-name=oxygen-gtk` unbroke scrolling, but then I had the ugly buttons again.

oxygen-gtk3 bug is reported at https://bugs.kde.org/show_bug.cgi?id=321284, an experimental patch will soon be attached to that bug.

I'm also having this issue with Adwaita in xfce.

Same here with Adwaita in xfce, and any other theme I've tried.
Scrolling works with the trackpad, but not with the scrolling button (4 and 5) of an external usb mouse.
It doesn't seem to affect all gtk3 applications though. For instance, scrolling (with an external mouse) works with evince, but not with evolution.

One thing that worked for me was setting GDK_CORE_DEVICE_EVENTS=1.

Bingo ! That worked. Thanks a bunch rlipman.

A note to any other amatuers coming across this post, if your window manager starts with a bash script that creates its own environment (like startx if you start from that), or my wmiirc in my case, add the line 'export GDK_CORE_DEVICE_EVENTS=1' to start all apps with that environment variable. You can check this is working by opening up a terminal with your window manager and typing 'export | grep GDK_CORE_DEVICE_EVENTS' and seeing if anything comes up. Hope this helps!

status?