It works, here is a quick and dirty test patch, when you release the key, the wet parameter of the dual delay quickly fades in, when you play, the signal is dry. http://falcontinuum.com/wp-content/uploads/2016/09/Delay-Gater.uvip_.zip
Ah yes, that’s the key and I now understand, thank you for the example Simon.
So the steps are:
1. Create layer with desired effect to be modulated.
2. Create at least two key groups in that layer, one for sound, one for linking (turn gain down)
3. Create retrigering envelope on the layer, set as legato
4. Modulate any parameter from the linking key group created in step 2 to the retrigering envelope created in step 3
5. Link the effect parameter created in step 1 to the retrigering envelope created in step 3
6. Edit modulation of the effect parameter to invert the action.
7. Enjoy