Currently, there is only "Visible" or "Invisible". Would be nice to get 1 or 2 additional options there, namely "50 % opacity" and "15 % opacity". These would make it simpler to place vias in multi-layer boards. One wouldn't be forced to constantly toggle copper zone visibility on/off. I know one can set the layer opacity as a whole to e.g. 15 %, but this also makes the traces barely visible.