The “Save securely on device” option to store the password for Threema 2.0 for desktop (or Threema Work 2.0 for desktop) may be grayed out on Linux devices. If you are running a window manager other than Gnome or KDE (e.g., Sway), you will need to export the environment variable XDG_CURRENT_DESKTOP=GNOME or XDG_CURRENT_DESKTOP=KDE in order to use GNOME Keyring or KWallet through the “Save securely on device” option in Threema and Threema Work.
You can make this variable permanent using an application like Flatseal, or by using the following command line:
Threema Private:
flatpak override --user --env=XDG_CURRENT_DESKTOP=GNOME ch.threema.threema-desktop
Threema Work:
flatpak override --user --env=XDG_CURRENT_DESKTOP=GNOME ch.threema.threema-work-desktop
If the aforementioned solution does not work, you can try to explicitly set the --password-store parameter to force usage of libsecret:
Threema Private:
flatpak run ch.threema.threema-desktop --password-store="gnome-libsecret"
Threema Work:
flatpak run ch.threema.threema-work-desktop --password-store="gnome-libsecret"
Please note: this solution is not limited to Gnome, as the name might imply, but can also help on KDE desktops or in other environments that use KWallet 5.
