Firefox doesn’t recognize the “ALT” keys anymore

firefoxkey-bindingUbuntu

Ubuntu 12.04, Firefox 13.0, xfce

For some reason, my Firefox installation has stopped paying attention to ALT keystroke combinations. That is, when I try an ALT-something key combination, I get the "something" as if ALT wasn't pressed at all. The "ALT" mechanism works fine in all the other apps I've tried; it used to work in Firefox (like, literally for years and years, until just the other day).

I've tried running on a new Firefox profile, and it behaves the same way, so I don't think it's a corrupted profile. I've got another laptop, different hardware, but essentially the same setup as this one, and Firefox and the "ALT" key get along fine there.

I have no idea where to even start trying to diagnose this. The general issue of keystroke processing on Linux is, I know, a fantastically complicated area, but since my "ALT" key seems to work perfectly well in every other application on the computer, I'm thinking this has something to do with some weird Firefox configuration thing.

What might be the problem? What can I do to investigate what's going wrong?

edit — Uninstalled/reinstalled Firefox, no effect. Still can't find another application on the system that doesn't understand the ALT key.

Best Answer

You may need to reinitialize your keyboard mapping

from an xterm run setxkbmap followed by xmodmap

_{Other things to check}

Remove lvl3:ralt_switch if present in /etc/default/console-setup

analyze the output from this procedure:

from xterm: xev | grep -B 4 -C 4 KeyPress
move mouse into the terminal window
make a keypress using LEFT-ALT
next make a keypress using RIGHT-ALT

Non XFCE-related stuff

It won't be exactly an answer to your problem, sorry for that, but still should be useful for someone at least. In Gnome it was fixed in recent Ubuntus. By it I mean treating Win not as a modifier key. In the old days, e.g. in Ubuntu 9.04, you had to do following change:

Go to System -> Preferences -> Keyboard, under Layouts tab click Layout options... button and in Alt/Win key behavior list choose Meta is mapped to Win keys (or Meta is mapped to Left Win) instead of Default.

What it really does? Changes altwin option in $HOME/.gconf/desktop/gnome/peripherals/keyboard/kbd/%gconf.xml file (or creates it if it does not exist):

<?xml version="1.0"?>
<gconf>
        <entry name="options" mtime="1298496603" type="list" ltype="string">
                <li type="string">
                        <stringvalue>altwin     altwin:meta_win</stringvalue>
                </li>
        </entry>
</gconf>

If you've chosen Left Win, then there will be following string value:

altwin     altwin:left_meta_win

In Ubuntu 10.10 it's not needed as Default apparently has changed.

But you have XFCE, not Gnome, so this rather won't help you.

XFCE-related stuff

I've downloaded Xubuntu (9.10), played with it a bit and finally found a solution.

Firstly, though, I must say that keyboard settings are really screwed in XFCE. In Settings -> Keyboard under Layout tab you don't have too many options. You cannot change XkbOptions there and even if you do it manually in ~/.config/xfce4/xfconf/xfce-perchannel-xml/keyboard-layout.xml, it will be overwritten. So I've changed /etc/default/console-setup by adding altwin:meta_win to XKBOPTIONS (use comma as separator if there are some other option(s) already). Still, no luck.

tl;dr

What's the solution?

Do not care about XFCE way of handling keyboard, because it's apparently broken. Use setxkbmap directly:

setxkbmap -option altwin:meta_win

(or left_meta_win, whatever you prefer)

Now you have to check that it really solved your problem. :)

How to apply it permanently?

echo -option altwin:meta_win >>~/.Xkbmap

It can be also done for all users by writing to /etc/X11/Xkbmap instead.

How can I quickly check if `altwin:meta_win` or `altwin:left_meta_win` has been applied?

setxkbmap -print

Line with xkb_symbols should have something like altwin(meta_win).

Best Answer

Other things to check

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