With natural scrolling, horizontal sliders behave backwards

Thank you for taking the time to report this bug and helping to make Ubuntu better. The issue you are reporting is an upstream one and it would be nice if somebody having it could send the bug to the developers of the software by following the instructions at https://wiki.ubuntu.com/Bugs/Upstream/GNOME. If you have done so, please tell us the number of the upstream bug (or the link), so we can add a bugwatch that will inform us about its status. Thanks in advance.

Status changed to 'Confirmed' because the bug affects multiple users.

Thank you for reporting this bug to Ubuntu.
Ubuntu 17.10 (artful) reached end-of-life on July 19, 2018.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test. If you then find the bug is still present in the newer Ubuntu version, please add a comment here telling us which new version it is in and change the bug status to Confirmed.

This issues is still present in Ubuntu 18.04.

$ lsb_release --all
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.1 LTS
Release: 18.04
Codename: bionic

$ gnome-shell --version
GNOME Shell 3.28.2

SCROLLED WINDOWS AND NATURAL SCROLLING
-----------------------------------------------------------

For scrolled windows, the input from the track-pad reverses...

  With natural scrolling DISABLED:
  - Sliding fingers down on a track-pad, slides the view down
  - Sliding fingers up on a track-pad, slides the view up

  And with natural scrolling ENABLED:
  - Sliding fingers down on a track-pad, slides the view up
  - Sliding fingers up on a track-pad, slides the view down

"Flipping" the behavior of a scrolled window based on whether or not natural scrolling is set, makes a lot of sense. That is how it should work.

VOLUME CONTROL AND NATURAL SCROLLING
-----------------------------------------------------------

However, "flipping" the behavior of a volume control, based on whether or not natural scrolling is set, *does not* make sense. Volume should always go up, when you slide up. Volume should always go down, when you slide down.

For volume control, the input from the track-pad should NOT reverse...

  With natural scrolling DISABLED:
  - Sliding fingers down on a track-pad, should cause volume to decrease
  - Sliding fingers up on a track-pad, should cause volume to increase

  With natural scrolling ENABLED:
  - Sliding fingers down on a track-pad, should STILL cause volume to decrease
  - Sliding fingers up on a track-pad, should STILL cause volume to increase

PROPOSED SOLUTION
-----------------------------------------------------------

In order to resolve this issue, I think we can apply the following rule:

  If
    org.gnome.desktop.peripherals.touchpad natural-scroll = true

  Then
    GtkVolumeButton widget should reverse the scroll event input

Essentially, the widget itself would undo the "flip" caused by setting natural-scrolling. Of course, if natural scrolling isn't set, the widget would behave as it normally does.

Issues is still present in 18.10. (I do see that the cosmic and disco tags were added).

Could someone report hat one upstream?

I opened this issue against gnome-shell, upstream.
https://gitlab.gnome.org/GNOME/gnome-shell/issues/1159

I did not report this bug against gtk+3.0. Should I do that as well?

This bug is still being tracked in bugzilla.

For reference, here are the upstream bugs:

GITLAB:
https://gitlab.gnome.org/GNOME/gnome-shell/issues/1159

BUGZILLA:
https://bugzilla.gnome.org/show_bug.cgi?id=724935
https://bugzilla.gnome.org/show_bug.cgi?id=703046

With 18.04 LTS, if you login with flashback, the volume slider in the sound settings as well as the volume slider that drops down when clicking the speaker indicator behave backwards even when natural scrolling is off.

With flashback, turning natural scrolling on actually makes both volume sliders behave as you would expect (up=up, down=down). Using "natural scrolling" is too unnatural to keep this setting however.

Still an issue in 20.04