Dual-function keys are one of the most versatile features in QMK. Getting them working for your own unique typing style can require lots of experimentation and adjustments, though. There has never been one single setting we could recommend users who are just getting started, until now.
Our newest option in the "Holding" settings of Oryx is called Chordal Hold, and it's one of the most requested features we've gotten. Our friend Pascal Getreuer created this QMK feature — it rocks. You may recognize Pascal from the very popular Achordion library; Chordal Hold is the latest version of this concept, simplified and now fully integrated into QMK.
Chordal Hold makes it easier to avoid accidental dual-function key shortcuts when typing letters on the same hand. This is particularly useful if you're using home-row mods. If you're typing quickly, you won't accidentally type "Resh" instead of "fresh", Ctrl + A instead of "day", and other funny held combinations anymore.
You can still trigger dual-function keys on the same hand, but you will need to hold the dual-function key the full length of your tapping term, then tap another key. So if I want to press Ctrl + C with one hand, I need to hold "D" (whose Hold function is Ctrl in my layout) for my tapping term, then hit "C". Or, I can hold "K" on my opposite hand and hit "C" without having to be so picky about the timing.
Configuring Chordal Hold
Even though Chordal Hold will help a lot when it comes to home-row mods, there are still some settings you can tweak to your liking.
Pascal recommends turning Permissive Hold on and using a relatively high tapping term (something around the default 200ms to 250ms). This is a good starting point because it gives you the best of both worlds: held actions of dual-function keys on the same hand must be done very deliberately (avoiding accidental modifiers) while held actions of dual-function keys on opposite hands can be done instantly thanks to Permissive Hold.
Keys Chordal Hold will and will not work on
Note that Chordal Hold applies to all dual-function keys in your layout. So, if you have dual-function thumb keys that switch layers, for example, try to prioritize assigning keys on the opposite side of the layer switch.
Conversely, not all multi-function keys are dual-function keys; some are tap dance keys, which Chordal Hold does not affect. It is important to note that some keys that do two things are not, in fact, dual-function keys: if a key has a held action that is not a modifier or an MO (momentary) layer switch, it gets created as a tap dance key instead and so it won't be affected by Chordal Hold.
To put it positively: Chordal Hold will work on the keys in your layout that send a letter when tapped, and a modifier (or a "held layer" switch) when held. That's what it's for.
While we're on the subject, any key with a double-tap or tap-then-hold action is not a dual-function key — it's a tap dance. If this sounds confusing, we have an article all about multi-function keys.
The quick way to see this in Oryx is by clicking "Advanced view" at the bottom left, and any dual-function keys will be labeled with a "D" while any tap dance keys will be labeled with a "T" or "+".
If you want to give home-row mods a try or you've tried them in the past and found them too fiddly, give Chordal Hold a try. It really is a game changer.
