Combo + &mt => Combo wins

[arialdomartini]

I would like the following behavior:

Key	When	Behavior
D	Tapped	D
D	Held down	Ctrl
F	Tapped	F
F	Held down	Shift
D+F	Tapped	G
D+F	Held down	Shift + Ctrl

Therefore, I configured:

Key	Configuration
F	&mt LSHIFT F
D	&mt LCTRL D

plus a combo:

combo_G {
  timeout-ms = <50>;
  key-positions = <12 13>;
  bindings = <&kp G>;
};

All works but the very last combination: D+F held down activate the combo instead of the 2 modifiers.

Any idea how to make it work?

[arialdomartini]

Browsing the past issues and comments, I found this that may be relevant:

https://github.com/zmkfirmware/zmk/issues/45#issuecomment-746399029

[caksoylar]

Combos capture key presses processed before regular behavior logic so this is normal. You can make the combo binding itself a mod-tap like &mt LC(LSHIFT) G so that you still get ctrl+shift on hold, or you can slightly stagger the key presses so that you don't trigger the combo.

QMK has a setting called COMBO_MUST_TAP that assumes that combo shouldn't fire if it is a long press on the source keys. Absent a setting like that there isn't a way for the firmware to know whether you intended a long press G or ctrl+shift.

[arialdomartini]

@caksoylar I works perfectly. Amazing. Thank you also for the hint on QMK. You are amazing.