Selfbuilt Firefox (Nightly) doesnt use the desktop entry

Because I use hardened_malloc I build Firefox myself, removing its builtin jemalloc so that it uses hardened_malloc too.

Unnecessary detail but it works well!

Now I made a fancy desktop entry looking like this:

[Desktop Entry]
Name=Firefox Build
Exec=/var/home/user/Firefox-Build/mozilla-unified/obj-ff-rel-opt/dist/bin/firefox %u
Icon=firefox
Type=Application
Categories=Network;WebBrowser;
MimeType=application/pdf;application/rdf+xml;application/rss+xml;application/xhtml+xml;application/xhtml_xml;application/xml;image/gif;image/jpeg;image/png;image/webp;text/html;text/xml;x-scheme-handler/http;x-scheme-handler/https;x-scheme-handler/ipfs;x-scheme-handler/ipns;
Actions=Main;Insecure;new-private-window

[Desktop Action Main]
Name=Main
Exec=/var/home/user/Firefox-Build/mozilla-unified/obj-ff-rel-opt/dist/bin/firefox -p Main %u

[Desktop Action Insecure]
Name= Insecure
Exec= mullvad-exclude /var/home/user/Firefox-Build/mozilla-unified/obj-ff-rel-opt/dist/bin/firefox -p Insecure %u

[Desktop Action new-private-window]
Name=Private Window
Exec=/var/home/user/Firefox-Build/mozilla-unified/obj-ff-rel-opt/dist/bin/firefox -p Main --private-window %u

This is really cool as I can launch a profile and even a custom command (here to spawn firefox without using my VPN for Captive Portal Logins and bad websites).

But for some reason when launching it, instead it opens a new window with the generic Wayland Icon.

What have I missed? It is Firefox nightly (mainly because I have no idea how to build point releases) and the window is called “Nightly” I think.

My uninformed wild guess would be an issue with StartupWMClass not being set. Similar to LatteDock/FAQ - KDE UserBase Wiki

1 Like

Thanks yes that will be it.

https://specifications.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html