Issues setting default apps for Dolphin File Types in Pop!_OS with Flatpak Applications

Help
,
1

Hi,

I’m on Pop!_OS 22.04 with Gnome, and I’ve installed Doplhin 25.04.3 from Flathub.

I want to set a default app for a specific file, so I go to “Properties” → “Open With” → “Change” and from the “File Type Editor” I want to choose a specific app from the list of installed apps (other Flatpak apps included). The problem is first that I see no apps in the list (for any file type) and second that I don’t know what to select from the OS file selector when I want to choose a Flatpak app, e.g. org.gnome.Loupe from /$HOME/.var/app/org.gnome.Loupe for images.

Could you please help?
Thanks

2

Dolphin follows the standard Association between MIME types and applications

You probably want to have a .desktop file for your flatpak, then it is easy.

The application should be in the Graphic section I imagine, unless the .destkop file explicitly set itself to be GNOME only (Recognized desktop entry keys | Desktop Entry Specification OnlyShowIn), maybe Dolphin filters on KDE applications.

You can find the .destkop file in ~/.local/share/applications/org.gnome.Loupe.desktop.

Also changing file association in nautilus (GNOME Files), should apply to Dolphin too.

3

I tried to add ~/.local/share/applications/org.gnome.Loupe.desktop to the list but it says that it’s not a binary file.
Then, I tried to add ~/.local/share/flatpak/app/org.gnome.Loupe/current/active/files/bin/loupe and Dolphin suddenly crashed and could not be reopened. To fix that I had to remove all content of file ~/.var/app/org.kde.dolphin/config/mimeapps.list…
From the flatpak run command I see the following output:

F: Not sharing "/usr/share/icons" with sandbox: Path "/usr" is reserved by Flatpak
Gtk-Message: 22:31:30.348: Failed to load module "xapp-gtk3-module"
Qt: Session management error: Could not open network socket
QApplication: invalid style override 'qt5ct' passed, ignoring it.
        Available styles: Breeze, Windows, Fusion
"applications.menu"  not found in  QList()
ASSERT: "offer.service()->offset() != 0" in file /run/build-runtime/kservice/src/sycoca/kbuildservicefactory.cpp, line 333
4

Having this issue too in Linux Mint Cinnamon 22.1.
Dolphin 25.04.3 flathub.

In the Mint config I set images to be opened with Pix. But in Dolphin all images open in Xviewer.

Is this a bug, or how to set this?

5

I uninstalled Xviewer and then Dolphin asked what to do and opens it nicely with Pix. That worked around my issue.

6

You can try refreshing the KDE System Configuration Cache:
kbuildsycoca6 or kbuildsycoca
Then restart dolphin, it might then work.