User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:135.0) Gecko/20100101 Firefox/135.0

Steps to reproduce:

Click a URL in another system application

Actual results:

A new Firefox window opens to the default home page (not to the URL clicked)

Expected results:

A new Firefox tab should open to the link clicked. This is what has always happened in previous versions for me until my most recent upgrade.

Further version info:
$ snap info firefox
name: firefox
summary: Mozilla Firefox web browser
publisher: Mozilla✓
store-url: https://snapcraft.io/firefox
contact: https://support.mozilla.org/kb/file-bug-report-or-feature-request-mozilla
license: unset
description: |
Firefox is a powerful, extensible web browser with support for modern web
application technologies.
commands:

• firefox
• firefox.geckodriver
  snap-id: 3wdHCAVyZEmYsCMFDE9qt92UV8rC8Wdk
  tracking: latest/stable
  refresh-date: today at 04:54 EDT
  channels:
  latest/stable: 136.0-3 2025-03-04 (5836) 270MB -
  latest/candidate: 136.0-3 2025-03-06 (5862) 270MB -
  latest/beta: 137.0b3-1 2025-03-07 (5870) 255MB -
  latest/edge: 138.0a1 2025-03-09 (5878) 286MB -
  esr/stable: 128.8.0esr-1 2025-03-04 (5821) 284MB -
  esr/candidate: 128.8.0esr-1 2025-02-24 (5821) 284MB -
  esr/beta: ↑
  esr/edge: ↑
  installed: 135.0-2 (5701) 270MB -

See also Bug 1952698

(In reply to Eiichi from comment #1)

See also Bug 1952698

That's just Nightly (138), this bug is filed against 135.0.2, and it's likely a problem with snap packages.

Some further context in case it's relevant: Yesterday a service required me to follow a link to register for that service (a URL which for some reason that I no longer remember I couldn't see nor copy), so I was forced to momentarily change my default web application to Chrome to be able to do so (in light of this bug).

After that worked, I went to change my default browser back to Firefox and I discovered that I wasn't able to: the only option my settings provided me was Chrome, despite that I have the FF snap installed.

I thought it might be relevant so I wanted to flag it. And I'm using Unity with Ubuntu in case that's relevant.

$ dpkg -l | grep ubuntu-unity
ii plymouth-theme-ubuntu-unity 22.10 all Ubuntu Unity plymouth theme
ii ubuntu-unity-backgrounds 24.10-0ubuntu1 all Default backgrounds in Ubuntu Unity
ii ubuntu-unity-desktop 0.19 amd64 The Ubuntu Unity desktop system
ii ubuntu-unity-settings 22.10-0ubuntu4 all Default settings for Ubuntu Unity

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 24.10
Release: 24.10
Codename: oracular