User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:80.0) Gecko/20100101 Firefox/80.0

Steps to reproduce:

(Open GNOME)
Press the super key and search for nightly; add firefox nightly to favorites. Open firefox nightly, then move the firefox nightly window to a new workspace (default keybiding is Shift+Super+Page Up/Down).

Actual results:

When firefox nightly opened it stayed on there was just one icon in the GNOME sidebar/taskbar/favorites bar (as expected) but when it was moved to a new workspace the icon was duplicated, one for when firefox nightly was favorited and another for the actual firefox nightly window, as shown in the screenshot.

Expected results:

There should be only one firefox nightly icon in the GNOME sidebar despite being moved to a new workspace (just like in regular, non-nightly firefox).

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

I have discovered additional odd behavior relating to this bug:

• Moving the firefox nightly window to a different workspace when other firefox nightly windows are open will not cause the bug
• Opening new firefox nightly windows when an open firefox nightly window is already bugged will cause the new windows to also be bugged

This can't be fixed on Mozilla side as Mozilla does not ship firefox .desktop file. It's distributed by Ubuntu. We may adjust the .desktop we ship for flatpak and maybe Snap if there's anyone (I'm not sure there's any in mozilla tree).

(In reply to Martin Stránský [:stransky] from comment #4)

This can't be fixed on Mozilla side as Mozilla does not ship firefox .desktop file. It's distributed by Ubuntu. We may adjust the .desktop we ship for flatpak and maybe Snap if there's anyone (I'm not sure there's any in mozilla tree).

Not quite; the application does generate a desktop file when the "set as default" functionality is used and no desktop file for the binary path exists already.