= Target "Track: Set automation touch state"

When you use REAPER's "Touch" automation mode, REAPER needs a way to know if you are currently touching the control element which is bound to the automation envelope or not.
As long as you keep touching it, it will overwrite existing automation.
As soon as you release it, REAPER will leave the envelope untouched.

Classical control surfaces implement this very intuitively by providing touch-sensitive faders.
With this target, you can easily reproduce exactly this behavior via ReaLearn.
You do this by mapping the touch event (which is usually nothing else than a MIDI note on/off message) to this target.
The touch state is scoped to a particular track and parameter type which you can choose in the *Type* dropdown.

However, ReaLearn wouldn't be ReaLearn if it wouldn't allow you to let totally different sources take control of the touch state.
For example, if you have a push encoder, you could map the "push" event to the touch state, allowing you to write automation only while you are touching the encoder.
Or if you don't have a push encoder, you could just use some spare button.