For the past 4 years, the Compose key hasn't worked for me in Firefox (and only Firefox) on my personal laptop. I tried a few times to solve it but never got anywhere with it. I had no idea why it stopped working because it'd worked fine for many more years prior and still worked fine on my work laptop (albeit on an older OS version). I chalked it up to an upgrade of something somewhere. I thought it might eventually fix itself.
It never did, but still, while upgrading from Ubuntu 20.04 to 24.04 last week, I hoped Compose support in Firefox might have been sorted out.
I was disappointed.
I was also baffled. How had such a glaring bug persisted for so long unfixed? I was lured by red herrings. Was it a different bug with the same outcome? Was Ubuntu's move from packaging Firefox as a .deb to a .snap implicated? Was the move from X11 to Wayland implicated? Was IBus broken? Did I need to use a different input method? I hated thinking about all of this. I just wanted my Compose key to work so I could more easily type important things like 👀 as Compose + Shift O O. It was frustrating.
So I searched a bit more persistently this time and with broader terms. Today, wading thru pages of crap results, I finally stumbled upon The Answer:
Reset the focusmanager.testmode preference in about:config from its overridden value of true to its default value of false.
You've got to be fucking kidding me, I thought. It can't be that easy, can it? I thought.
It was that easy. I nearly shouted at my computer. I would have shouted at my computer if the kids weren't asleep.
Why would that preference even be set‽ I thought. Well, it turns out that maybe Selenium or maybe some other browser-based testing frameworks or, christ, lots of things might set it automatically to make their tests run faster? Grarrr.
The details of how this came to be set for me in particular aren't clear. It might have been geckodriver? I recall (briefly) pointing it at an existing Firefox instance loaded with my main profile. But the timeline of events doesn't make sense there. And to make it less clear, I can see how the preference might have been set by something and then remained a latent bug until later something else about the input method or windowing system changed regarding focus. I'm not the only one lacking clarity either.
What I'm crystal clear about though is this:
I hate software.