Use information about layers and distance everywhere..

[AntonioGPS]

In preview mode, you can work with layers
In Variable settings wizard however, you work with distances, although I recognize that a visual layer can be seen for help

I believe that you should allow to work with either distances and/or layers as a choice in every situation, tool or window. This will help in some cases were a high precision is required.

In any case, i don't know the relationship between distance and layer, and this produces some discomfort and annoyance