KDE assign meta key to trigger the menu window but depending on the situation this does not always work.
This issue seem to be fixed on newer version of KDE but this is not yet widely distributed.
How to fix it ?
~/.config/kwinrc, adding the following lines: [ModifierOnlyShortcuts]
Meta=
Then restart kwin with kwin_x11 --replace & disown.
Map a new key to meta with xmodmap -e 'keycode 133 = F14' (F14 is used here)
Set F14 as the shortcut to trigger the menu (right click on the menu then settings)
To make this permanent, step 3 needs to be added to startup
Update
Xmodmap changes does not seem to be kept after sleep/resume, here is how to set xmodmap on system resume with systemd: (non systemd user can use this)
Create xkeyboard resume script:
touch /usr/lib/systemd/system-sleep/xkeyboard; chmod 755 /usr/lib/systemd/system-sleep/xkeyboard
Edit xkeyboard and fill it with:
#!/bin/bash
case $1 in
pre)
exit 0
;;
post)
export DISPLAY=:0
sleep 10
xmodmap -e 'keycode 133 = F14'
;;
esac