package libgtk-3-0 3.18.9-1ubuntu3.2 failed to install/upgrade: trying to overwrite shared '/etc/gtk-3.0/settings.ini', which is different from other instances of package libgtk-3-0:amd64

[Leszek]

Problem during standard "sudo apt upgrade" procedure

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: libgtk-3-0 3.18.9-1ubuntu3.2
ProcVersionSignature: Ubuntu 4.8.0-46.49~16.04.1-generic 4.8.17
Uname: Linux 4.8.0-46-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.5
Architecture: amd64
Date: Fri Apr 7 20:55:38 2017
DuplicateSignature:
 package:libgtk-3-0:3.18.9-1ubuntu3.2
 Unpacking libgtk-3-0:amd64 (3.18.9-1ubuntu3.3) over (3.18.9-1ubuntu3.2) ...
 dpkg: error processing archive /var/cache/apt/archives/libgtk-3-0_3.18.9-1ubuntu3.3_amd64.deb (--unpack):
  trying to overwrite shared '/etc/gtk-3.0/settings.ini', which is different from other instances of package libgtk-3-0:amd64
ErrorMessage: trying to overwrite shared '/etc/gtk-3.0/settings.ini', which is different from other instances of package libgtk-3-0:amd64
InstallationDate: Installed on 2016-02-28 (404 days ago)
InstallationMedia: Ubuntu-GNOME 16.04 LTS "Xenial Xerus" - Alpha amd64 (20160225.1)
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.20
SourcePackage: gtk+3.0
Title: package libgtk-3-0 3.18.9-1ubuntu3.2 failed to install/upgrade: trying to overwrite shared '/etc/gtk-3.0/settings.ini', which is different from other instances of package libgtk-3-0:amd64
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

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