This is a common complaint. The only way to prevent SONAR refreshing all the controller lanes is to avoid closing it - i.e. leave the PRV open in the multidock and hide the dock when not in use (Hotkey D to toggle show/hide) or keep it in a different screenset.
Lanes will also refresh when changing which tracks are selected using the 'Tracks' dropdown in the PRV. You can avoid that by getting all the tracks you expect to be editing opened in the PRV, closing all the extra lanes, and then using the Track Pane at the right (see View options if it's not showing) to control which tracks are shown and which are editable.