With 'dwell-click' enabled there is no scrolling with mousewheel in gtk3 windows

[Doug McMahon]

Test Case:
enable dwell-click in System Settings > Universal access > Pointing & Clicking > Hover click or
gsettings set org.gnome.desktop.a11y.mouse dwell-click-enabled true

Try to scroll in a scroll-able gtk3 window with mouse wheel, nothing happens
Scrolling is possible in gtk2 windows like Firefox

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: mousetweaks 3.12.0-1ubuntu1
ProcVersionSignature: Ubuntu 3.16.0-6.11-generic 3.16.0-rc7
Uname: Linux 3.16.0-6-generic x86_64
ApportVersion: 2.14.4-0ubuntu2
Architecture: amd64
CurrentDesktop: Unity
Date: Thu Aug 7 19:33:45 2014
InstallationDate: Installed on 2014-07-31 (7 days ago)
InstallationMedia: Ubuntu 14.10 "Utopic Unicorn" - Alpha amd64 (20140729)
SourcePackage: mousetweaks
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

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

[giffel (xgiffel)]

Still present on Xubuntu 16.04. Evince document reader is affected for example.

[giffel (xgiffel)]

LibreOffice 5.2.2.2 on Xubuntu 16.10 is also affected. The problem starts spreading to more and more applications as GTK3 being adopted.

[miguel (miguelmartinezlopez)]

A possible workaround is explained here:
  https://forums.linuxmint.com/viewtopic.php?t=242806

Adding this:
  GDK_CORE_DEVICE_EVENTS=1
at the end of ~/.profile solves this issue.

GTK3 uses the X Input Device Extension Library by default. It seems that for some reason this extension is the source of the problem.

Setting that environment variable, GKT3 only reacts to core X input events. It doesn't use that extension library.

[miguel (miguelmartinezlopez)]

Sorry, adding this at the end of ~/.profile solves the problem for the mentioned reason:
   export GDK_CORE_DEVICE_EVENTS=1

I forgot to add "export".