Running xfce4-session inside Hyprland breaks GIMP icon loading on startup

Software involved

• GIMP version: 3.0.0
• Xfce session version: 4.20.0
• OS: Arch Linux
• Compositor: Hyprland (Wayland) 0.47.2

Description

When GIMP is loaded, it fails to load any icon. However, if I go to Edit > Preferences > Interface > Icon Theme and change it to anything else and then back, then the original theme loads properly.

Here is a screenshot with the Default icon theme (with symbolic icons selected):

Here is how it looks after toggling the icon theme twice in the preferences (i.e. how it should look at startup):

This seems to occur only when running Xfce session from Hyprland. If I don't start Xfce session in Hyprland, it works properly. Alternatively, if I keep Xfce session enabled, but use the GIMP AppImage instead of the native Arch Linux package, the icon loading works.

I don't know how to debug this further, so I could do with some pointers on how to proceed.

Steps to reproduce

1. Open GIMP
2. Observe the missing icons
3. In the Edit menu, click on Preferences.
4. In the left panel with the sections, click on the Icon Theme subsection under the Interface section.
5. Change the icon theme to something else.
6. Observe that the icon theme has changed, and now works.
7. Change the icon theme back to the original theme.
8. Observe that your preferred icon theme works properly now.

Upstream issues

• GIMP: https://gitlab.gnome.org/GNOME/gimp/-/issues/13151
• Arch packaging: https://gitlab.archlinux.org/archlinux/packaging/packages/gimp/-/issues/8

changed title from Running xfce4-session inside Hyprland breaks GIMP icon loading to Running xfce4-session inside Hyprland breaks GIMP icon loading on startup

added 5. Wayland label

added 5. Icons label

The issue is not with xfce4-session, but with xfsettingsd. I suppose it's some weird interaction with the gtk-module that's loaded to ensure synchronization with GtkSettings on wayland, but I can't see what it is exactly at this stage. Investigations welcome!

moved from xfce4-session#215 (moved)

Having same problem with Xfce on Wayland with using Wayfire or LABWC in:

• Arch Linux (virtual used for testing Xfce with all latest packages)
• Xubuntu 24.04 with Xfce 4.20 (from XubuntuDev PPA's) and GIMP 3.0 (from UbuntuHandbook GIMP3 PPA) (my primary system on primary notebook)

If relogin to Xfce4-X11, Wayfire(without Xfce) or LABWC(without Xfce) session, in all work OK...

Yes, nothing specific to hyprland here, or to any compositor I think, it's really xfsettingsd and gimp…

And is strange, in GIMP Preferences is not need exact switch in "Icon Theme" to another theme and back, but change some other (ex.: System Resources/Minimal number of undo levels) setting and then only switch to "Icon Theme".

as @rharish101 tried AppImage, i now try Flatpak and in Xfce@Wayfire/Wayland icons without problem

Yes, really xfsettingsd, if i kill it then GIMP3 run with icons :-)

So i create as really dirty "workaround" wrapper script to run: /usr/local/bin/gimp-3.0

#!/bin/sh
killall -s SIGSTOP xfsettingsd
/usr/bin/gimp-3.0 &
sleep 30
killall -s SIGCONT xfsettingsd

Although GIMP3 for me starting to gui in about 4-5s, with sleep <26s, after GIMP3 run with icons ok, in moment xfsettingsd is SIGCONT, all icons in GIMP3 disappear, with sleep >=26s icons keep :-)

I can confirm that this workaround works.

So it's the GtkSettings:gtk-icon-theme-name setting that our gtk-module sets from the xfconf /Net/IconThemeName property of the xsettings channel that's causing the problem, but I'm not sure what to do about it. There's no way to tell gtk to load the module earlier when gimp starts, or even not to load the module at all, as far as I know.