Right Option (AltGr) and Left Option (Alt) producing same output on macOS – need to differentiate for shortcut use

[moritz1000]

Hi there,

I'm using a keyboard configured with QMK firmware, targeting macOS. I've explicitly mapped the modifier keys as follows:

KC_LALT = (Left Option)

KC_RALT = (Right Option / AltGr)

According to the QMK documentation:
https://docs.qmk.fm/keycodes_basic#modifiers

Key	Aliases	Description
KC_LEFT_ALT	KC_LALT, KC_LOPT	Left Alt (Option)
KC_RIGHT_ALT	KC_RALT, KC_ROPT, KC_ALGR	Right Alt (Option/AltGr)

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Problem:

Currently, both Left Option + A and Right Option + A result in the same character output: Ä.

However, I'd like to replicate the Windows-like behavior where:

1. Right Option (AltGr) → triggers extended characters like Umlaute (e.g., Ä)

2. Left Option (Alt) → remains available for shortcuts (e.g., Left Option + L = lists the contents of the current directory in fish shell)

Is this intended behavious with EurKEY-macOS? So no discrimination between Left & Right Option?

Or is this a problem with QMK / macOS and is there a way so that only Right Option produces special characters, and Left Option functions independently for system shortcuts?

[moritz1000]

I can confirm with Key Codes
That my keyboard is sending a different key code for Left Option (1) and Right Option (2) so I don't think that the problem lies with my hardware/keyboard side and is either with macOS or with EurKEY-macOS

Thank you for your help!

[felixfoertsch]

Hello! Thank you for the report. Imho for macOS-Keyboards it doesn't make sense to distinguish between left-option and right-option, so both keys should emit the same behavior. However, I am not sure if the key codes should be different or not. I would assume they should be different, since they are two different physical keys.

I'd like to replicate the Windows-like behavior [...]

Replicating Windows is not something this project tries to achieve.

[moritz1000]

Replicating Windows is not something this project tries to achieve.

Hello,
thank you for pointing this out.

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As a side note, I found a workaround for my problem with EurKEY-macOS and my terminal (Ghostty).
Setting macos-option-as-alt = left in Ghostty allows me to:

• use my left Option key for shortcuts e.g. left Option + l = "lists the contents of the current directory in fish shell"
• while still retaining my right Option key for EurKEY e.g. right Option + a = ä

Though I still have not found a workaround for other programs, where I would need my left Option key for build-in shortcuts.

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Again thank you for taking your time and replying to my issue.

[elburro1887]

I am also looking for a solution to this issue, i need only the right option key to trigger EurKEY so that the left one is free for other purposes.

Is this in anyway possible?