Help: Missing Several Apps in Show Apps

I’m running NixOS. Most of my applications show up in the overview Show Apps menu, but several do not, and I cannot figure out why.

$XDG_DATA_DIRS includes /home/$USER/.nix-profile/share/applications/, and that contains both applications/zotero.desktop and applications/mpv.desktop. However, of those two, only Zotero is showing up in my application view. Both are valid, when checked with desktop-file-validate. All of the programs themselves are properly in my $PATH, and I can start them from the terminal. So, I’m not sure why Gnome is seeing one, but not the other.

There are several programs that are not showing up, and many that are. I have not found a pattern here.

Any advice on how to debug the missing Desktop entry and make it visible in Gnome? Is there a log somewhere that would indicate what error is being triggered?

Likely because $HOME/.nix-profile/share is not in the $XDG_DATA_HOME or $XDG_DATA_DIRS environment variables.

I recommend asking on a NixOS support forum how to properly integrate GNOME on NixOS.

Thank you so much for responding.

Likely because $HOME/.nix-profile/share is not in the $XDG_DATA_HOME or $XDG_DATA_DIRS environment variables.

$XDG_DATA_DIRS does contain $HOME/.nix-profile/share, which is where my confusion comes from. And, as far as I can tell, both working and non-working desktop files are in the same directory, leading me to think it is not an environment variable issue.

That said, it looks like $XDG_DATA_HOME is currently unset on my system.

I recommend asking on a NixOS support forum how to properly integrate GNOME on NixOS.

Will do. And sorry for bothering upstream about my issue.

That said, is there any Gnome-specific documentation about .desktop file handling that I could read, which may help me clarify what’s going wrong? Alternatively, any debug logging that would contain Gnome’s decisions around this? (Running journalctl -u gnome-session-manager@gnome.service --user did not turn up anything, but I could be looking in the wrong place or have the wrong logging level enabled by default.)

Any information does not have to be NixOS-specific, of course. I am just looking for a place to start.

Thank you!