When I create a new parcel polygon, I go to symbology to "more" then select " regenerate symbols" When it regenerates it gives all the surrounding parcels the default color which is gray & gives the new parcel a color. I usually have to hit regenerate symbols again or select "add all values" then go back to "regenerate symbols" to make the default color go away. My primary symbology is "unique values" and my field is the lot numbers.
