Flag types should always be over other series
I think flag types should always be over other series? For example, http://jsfiddle.net/680bg7sq/, flags are rendered below another series, because the order of series is such. In my case, series are loaded asynchronously (using addSeries) because I am loading them from the server (and various data takes various time). While for normal series this is often OK, for flags it is not?
This is default behavior - zIndex for series is the same as index in the series array. That's the reason to use zIndex option: http://api.highcharts.com/highstock#plotOptions.series.zIndex - see demo: http://jsfiddle.net/680bg7sq/1/