[Bug] XMonad.Util.EZConfig : single modkey doesn't works with special keys

[thealio]

Hi !

Usinig xmonad with XMonad.Util.EZConfig , I've noticed the following

This keybind , using M as an only modkey, doesn't work

^++^ subKeys "Mouse emulation"
 [ ("M-+",  addName "Left click mouse"   $ spawn $ "xdotool click 1") ]   

But, if I use two modkeys, the command is performed correctly

^++^ subKeys "Mouse emulation"
 [ ("M-C-+",  addName "Left click mouse"   $ spawn $ "xdotool click 1") ]   

This happens also with other special keys like the F1-F24 keys , the End key and the insert keys, and probably with other keys

xmonad.hs.txt

[SimSaladin]

Are you sure you don't have conflicting binds defined outside of xmonad with xbindkeys or something similar? I tried adding a "M-+" binding to your config and then in ghci:

> :load xmonad.hs
> xc = addDescrKeys' ((mod4Mask, xK_F1), showKeybindings) myKeys myDefaults
> isJust $ M.lookup (mod4Mask, xK_plus) $ keys xc xc{layoutHook = Layout Full}
True

So the key binding appears to be added as expected (with my version of xmonad-contrib anyway).

[geekosaur]

FWIW I noticed when I upgraded to Ubuntu 24.10 that many (not all) of my keybindings had to be pressed twice to work. If I perform some other xmonad action then I again have to press it twice, otherwise after the first press subsequent ones work as expected. I made no change to my xmonad config, just rebuilt it for the new dependencies. This smells like an upstream bug which is unlikely to be fixed (Ubuntu is apparently dropping X11 support as of 25.10).

(This behavior is incompatible with "something else is intercepting them" because that would intercept all presses, not just the first.)

[slotThe]

Could be that + is interpreted as S-= or something? Depending on the locale settings. Though I guess that would not explain why M-C-+ apparently works

[geekosaur]

Hm, I missed that. One must remember that keybindings always use base keycodes; since + is shifted on US keyboards, you must use S-= to get it unless you have rebound some key to send + with no modifiers. The X11 key binding mechanism we use requires this. Automatic conversion requires analyzing the current keymap, which can potentially be quite complicated when Xkb is involved and raises questions about what to do when you've already included one or more of the required modifiers in the binding.

[thealio]

Are you sure you don't have conflicting binds defined outside of xmonad with xbindkeys or something similar? I tried adding a "M-+" binding to your config and then in ghci:

> :load xmonad.hs
> xc = addDescrKeys' ((mod4Mask, xK_F1), showKeybindings) myKeys myDefaults
> isJust $ M.lookup (mod4Mask, xK_plus) $ keys xc xc{layoutHook = Layout Full}
True

So the key binding appears to be added as expected (with my version of xmonad-contrib anyway).

Hi
I'm sure about key binding conflicts, no key binding conflicts
I'm on arch linux

[SimSaladin]

Then, assuming that the keybinding gets registered correctly (as would appear to be the case), it should follow that you are not triggering it when you press whatever you believe to be the key combination M-+.

As was pointed above, that particular binding is practically unusable on almost all keyboard layouts because of the '+' keycode being shifted. Only on a handful of layouts this isn't so. In order to get to the bottom of your situation, could you tell us what layout you are using (setxkbmap -query)?

You may also find it useful to check the key and modifiers that are emitted when you press an affected binding on your keyboard. One way to do this is to run xbindkeys --multikey and press the keys.