ui/src/main/java/ucar/util/prefs/ui/PrefPanel.java
public Field addField(Field fld) {
    addField( fld, cursorCol, cursorRow, null);
    cursorRow++;
    return fld;
  }
public Field addField(Field fld) {
    addField( fld, cursorCol, cursorRow, null);
    cursorRow++;
    return fld;
  }
Add a field created by the user.
@param fld add this field.