Extracted from a test VM by guiverc after fighting with the systemd unit file for xdg-desktop-portal to get it to go into verbose mode.
Some observations:
1. Firefox is trying to call org.freedesktop.portal.FileChooser. The provided "method" in xdg (is that what you call it, a method?) is org.freedesktop.impl.portal.FileChooser. Dunno if the .impl missing in one of those means anything.
2. Running "/usr/libexec/xdg-desktop-portal --verbose --replace" in a terminal fixes the problem while that command is left running. The problem immediately resurfaces when the process is terminated.
3. XDG_CURRENT_DESKTOP appears to be set correctly, all files appear to be where they should, and you can even see xdg-desktop-portal loading the right file, so I think smcv's hunch is right about LXQt not copying things into the "activation environment" correctly.
Sep 22 06:50:39 lubuntu dbus-daemon[1698]: [session uid=1000 pid=1698] Activating via systemd: service name='org. freedesktop. portal. Desktop' unit='xdg- desktop- portal. service' requested by ':1.170' (uid=1000 pid=7686 comm="/ snap/firefox/ 3145/usr/ lib/firefox/ firefox" label=" snap.firefox. firefox (enforce)") portal. service - Portal service... portal[ 8799]: XDP: Looking for portals configuration in '/home/ lubuntu/ .config/ xdg-desktop- portal/ lubuntu- portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/home/ lubuntu/ .config/ xdg-desktop- portal/ portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/etc/xdg/ xdg-Lubuntu/ xdg-desktop- portal/ lubuntu- portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/etc/xdg/ xdg-Lubuntu/ xdg-desktop- portal/ portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/etc/xdg/ xdg-desktop- portal/ lubuntu- portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/etc/xdg/ xdg-desktop- portal/ portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/etc/xdg- desktop- portal/ lubuntu- portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/etc/xdg- desktop- portal/ portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/home/ lubuntu/ .local/ share/xdg- desktop- portal/ lubuntu- portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/home/ lubuntu/ .local/ share/xdg- desktop- portal/ portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/usr/share/ Lubuntu/ xdg-desktop- portal/ lubuntu- portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/usr/share/ Lubuntu/ xdg-desktop- portal/ portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/usr/local/ share/xdg- desktop- portal/ lubuntu- portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/usr/local/ share/xdg- desktop- portal/ portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/usr/share/ xdg-desktop- portal/ lubuntu- portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/usr/share/ xdg-desktop- portal/ portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/var/lib/ snapd/desktop/ xdg-desktop- portal/ lubuntu- portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/var/lib/ snapd/desktop/ xdg-desktop- portal/ portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/usr/share/ xdg-desktop- portal/ lubuntu- portals. conf' portal[ 8799]: XDP: Looking for portals configuration in '/usr/share/ xdg-desktop- portal/ portals. conf' portal[ 8799]: XDP: load portals from /usr/share/ xdg-desktop- portal/ portals portal[ 8799]: XDP: loading /usr/share/ xdg-desktop- portal/ portals/ gnome-keyring. portal portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. Secret portal[ 8799]: XDP: loading /usr/share/ xdg-desktop- portal/ portals/ kde.portal portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. Access portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. Account portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. AppChooser portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. Background portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. Email portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. FileChooser portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. Inhibit portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. Notification portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. Print portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. ScreenCast portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. Screenshot portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. RemoteDesktop portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. Settings portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. DynamicLauncher portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. GlobalShortcuts portal[ 8799]: XDP: loading /usr/share/ xdg-desktop- portal/ portals/ lxqt.portal portal[ 8799]: XDP: portal implementation supports org.freedesktop .impl.portal. FileChooser portal[ 8799]: XDP: providing portal org.freedesktop .portal. MemoryMonitor portal[ 8799]: XDP: providing portal org.freedesktop .portal. PowerProfileMon itor portal[ 8799]: XDP: providing portal org.freedesktop .portal. NetworkMonitor portal[ 8799]: XDP: providing portal org.freedesktop .portal. ProxyResolver portal[ 8799]: XDP: providing portal org.freedesktop .portal. Trash portal[ 8799]: XDP: providing portal org.freedesktop .portal. GameMode portal[ 8799]: XDP: providing portal org.freedesktop .portal. Realtime por[8799] : No skeleton to export p.portal. Desktop' portal. service - Portal service. portal[ 8799]: XDP: org.freedesktop .portal. Desktop acquired
Sep 22 06:50:39 lubuntu systemd[1670]: Starting xdg-desktop-
Sep 22 06:50:39 lubuntu xdg-desktop-
Sep 22 06:50:39 lubuntu xdg-desktop-
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Sep 22 06:50:39 lubuntu dbus-daemon[1698]: [session uid=1000 pid=1698] Successfully activated service 'org.freedeskto
Sep 22 06:50:39 lubuntu systemd[1670]: Started xdg-desktop-
Sep 22 06:50:39 lubuntu xdg-desktop-
Extracted from a test VM by guiverc after fighting with the systemd unit file for xdg-desktop-portal to get it to go into verbose mode.
Some observations:
1. Firefox is trying to call org.freedesktop .portal. FileChooser. The provided "method" in xdg (is that what you call it, a method?) is org.freedesktop .impl.portal. FileChooser. Dunno if the .impl missing in one of those means anything.
2. Running "/usr/libexec/ xdg-desktop- portal --verbose --replace" in a terminal fixes the problem while that command is left running. The problem immediately resurfaces when the process is terminated.
3. XDG_CURRENT_DESKTOP appears to be set correctly, all files appear to be where they should, and you can even see xdg-desktop-portal loading the right file, so I think smcv's hunch is right about LXQt not copying things into the "activation environment" correctly.