Dual-Function keys

Dual-functions keys are keys that combine a TAP and a MOD/LAYER.

Simply put, when a dual-function key is tapped, it produces a single keystroke (TAP). However, when it is held down or used in combination with another key, it functions as a modifier key or layer access (MOD/LAYER).

Auto-repeat

The most noticeable difference between standard keys and dual-function keys is the method of activating auto-repeat.

To auto-repeat: Press and release (TAP), then, press again (and hold).

Opposite MODs as TAPs

All dual-function MODs on the opposite side will be considered as TAP, improving the reactivity of these combinations by sending the TAP at keypress.

When a single MOD is used, there are no differences, but in case of combinations like Super + Shift + ... or or Control + Shift + ... , the MODs have to be done with the same hand (using the other hand to complete the combination with a TAP key). This is very convenient as Shift is available on both thumbs.

Alt is always available on both side since it isn't a dual-function key.

Pending MODs 🖱

Pending MODs are MODs on dual-function keys that are fired immediately at keypress in order to be used in conjunction with a mouse click. If the MOD is not used and the key is relased quickly, the MOD will be cancelled and the TAP will be sent instead.

A few applications react on release of the MODs themselves:

• Microsoft Windows launches the start menu when releasing Super
• VirtualBox unfocuses the virtual desktop when right Control is released

When using these software, its better do disable Pending MODs on the corresponding keys.

That's why by default, they are enabled only on left Shift and Control but they can be configured individually and different firmwares are available.