This screenshot shows the setting I created in xfce4-settings-manager in order to fix the problem.
** Attachment added: "setting to set" https://bugs.launchpad.net/ubuntu/+source/xubuntu-meta/+bug/1756187/+attachment/5080832/+files/xfce4-settings-manager.png ** Description changed: + To reproduce: + + Install Xubuntu 18.04 + Open Appearance settings -> Icons and set to ubuntu-mono-light + Open xfce4-settings-manager + + Result: + + "Mouse and Touchpad" settings has no icon. The same icon is missing + in a few other places too. + This is due to some change in the gnome settings. Icon themes can inherit from other themes. If an icon is still missing then the "hicolor" theme is checked. However, Gtk+2 and Gtk+3 both also do some undocumented checks. + + This affects pretty much any icon theme that does not explicitly inherit + from "gnome", which is quite a lot of themes. It even affects adwaita-icon-theme if you do not have adwaita-icon-theme-full installed too (and -full is not installed by default.) Gtk+3 is hardcoded to check "Adwaita" and "gnome". "gnome" is where those missing icons are. But we are not using Gtk+3 yet. Gtk+2 checks a xsetting called /Net/FallbackIconTheme. This is not set on either my 16.04 system or my 18.04 system, yet my 16.04 system can find the - missing icons in "gnome". 18.04 however cannot. Setting this key (in + missing icons in "gnome". 18.04 however cannot. Setting this key (in xfce4-settings-editor) fixes the problem. I have not yet figured out why this was not necessary in 16.04. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: xubuntu-desktop 2.223 ProcVersionSignature: Ubuntu 4.15.0-12.13-generic 4.15.7 Uname: Linux 4.15.0-12-generic x86_64 ApportVersion: 2.20.8-0ubuntu10 Architecture: amd64 Date: Thu Mar 15 21:41:54 2018 InstallationDate: Installed on 2018-03-15 (0 days ago) InstallationMedia: Xubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180315) SourcePackage: xubuntu-meta UpgradeStatus: No upgrade log present (probably fresh install) ** Description changed: To reproduce: - Install Xubuntu 18.04 - Open Appearance settings -> Icons and set to ubuntu-mono-light - Open xfce4-settings-manager + Install Xubuntu 18.04 + Open Appearance settings -> Icons and set to ubuntu-mono-light + Open xfce4-settings-manager Result: - "Mouse and Touchpad" settings has no icon. The same icon is missing - in a few other places too. + "Mouse and Touchpad" settings has no icon. The same icon is missing + in a few other places too. + + This affects pretty much any icon theme that does not explicitly inherit + from "gnome", which is quite a lot of themes. It even affects adwaita-icon-theme if you do not have adwaita-icon-theme-full installed too (and -full is not installed by default.) This is due to some change in the gnome settings. Icon themes can inherit from other themes. If an icon is still missing then the "hicolor" theme is checked. However, Gtk+2 and Gtk+3 both also do some undocumented checks. - - This affects pretty much any icon theme that does not explicitly inherit - from "gnome", which is quite a lot of themes. It even affects adwaita-icon-theme if you do not have adwaita-icon-theme-full installed too (and -full is not installed by default.) Gtk+3 is hardcoded to check "Adwaita" and "gnome". "gnome" is where those missing icons are. But we are not using Gtk+3 yet. Gtk+2 checks a xsetting called /Net/FallbackIconTheme. This is not set on either my 16.04 system or my 18.04 system, yet my 16.04 system can find the missing icons in "gnome". 18.04 however cannot. Setting this key (in xfce4-settings-editor) fixes the problem. I have not yet figured out why this was not necessary in 16.04. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: xubuntu-desktop 2.223 ProcVersionSignature: Ubuntu 4.15.0-12.13-generic 4.15.7 Uname: Linux 4.15.0-12-generic x86_64 ApportVersion: 2.20.8-0ubuntu10 Architecture: amd64 Date: Thu Mar 15 21:41:54 2018 InstallationDate: Installed on 2018-03-15 (0 days ago) InstallationMedia: Xubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180315) SourcePackage: xubuntu-meta UpgradeStatus: No upgrade log present (probably fresh install) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1756187 Title: Some icon themes have missing icons due to missing fallback setting. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xubuntu-meta/+bug/1756187/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
