On a compact keyboard (Cherry G84-4100LCMGB-0), pressing the keys I + O + N simultaneously seems to trigger Control + O.

Looking into Karabiner-EventViewer, pressing I + O + N then releasing N + O + I triggers Left Control:

eventType:key_down        code:0xc        name:i               misc:
eventType:key_up          code:0xc        name:i               misc:
eventType:key_down        code:0x12       name:o               misc:
eventType:key_down        code:0xe0       name:left_control    misc:
eventType:key_up          code:0x12       name:o               misc:
eventType:key_up          code:0xe0       name:left_control    misc:

I sometimes inadvertently press the three keys together when typing words like STATION, and it messes up the typing. How can I disable this behaviour? I've tried adding this snippet to karabiner.json but without success:

    "type": "basic",
    "from": {
        "simultaneous": [
                "key_code": "i"
                "key_code": "o"
                "key_code": "n"

Other similar key combinations seem to trigger Left Control (U + I + T for instance). This is unrelated to the System Preferences → Keyboard → Shortcuts, as the problem persists even after disabling all of these shortcuts.

  • Some keyboards just can't transmit as many simultaneous key-presses as others. I know the Apple wired keyboards can do at least 4 modifiers and 3 letters simultaneously [I haven't tested the absolute max], but there are many that can't. I'd double-check the same combo on an Apple keyboard. – Tetsujin May 29 at 9:44

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