In stock chart, when adding multiple series to a navigator you use "showInNavigator: true", but there doesn't seem to be a "showOnlyInNavigator". So In order to add multiple series to the navigator which aren't in the main graph, I have to add them using "showInNavigator" and then attach a load event to hide those series from the main graph. A "showOnlyInNavigator" option would make this much simpler/cleaner.
Thank you for your suggestion. Note that you can use the "visible" option on the main series to hide it from the chart and thus show only in navigator.