Where can I choose the layer to follow in a trace option. I try to reshape a polygon on an other one. I found the trace option but not the option to select a specific layer to make the trace. With O I only fond that the choice is to follow selected one.
If a layer is snappable it's also traceable, so if you don't want to trace along a particular layer, turn off snapping for that layer in the List By Snapping view in the Contents pane:
You can also make a particular layer the only snappable layer:
Ok, think is my English the problem. I'm mistaken the selection of the polygon I need to work on and the selection of the layer to trace on. So if I understand correctly, if I want to trace on a polygon B I select my polygon A to work on and in snapping, only select the polygon B to use for my trace.
After more than 20years with arc view and arcmap, new thinking to do.
The first solution regarding turning on snapping is useful if you have many layers in your map and you only want to trace features in a particular layer without other layers interfering.
Does that help?