There seems to be some inconsistancy on auto changing widths when
starting to route nets that belongs to a class.
Diff wires do seem to change width, but not singleend signals. It's nice
that diff signals do it, but maybe all classed signals having width!=0
should do this.
Then it would be nice if this only happened when started from pads/smd
or via. If grabbing an airwire starting from a wire, it sounds more
practical to continue this wire width, don't you think?