Comment 5 for bug 1670422

I am thinking this dialog should be modified (rewritten) to allow swapping of tracks (and vias) only, only on copper layers.

The purpose of this dialog is to modify track layers when changing the number of copper layers of a board.

For instance, using 8 layers instead of 6 layers in a partially routed board often imply moving the inner 4 layer to inner 6 layers (this is especially true if you are using microvias, or if you want to create a new copper plane)