Hi,
I am using igScheduler and I am having a problem when I add more than 10 appointments in a single day. I have also tried it on your jsFiffle demo and occures the same. (http://jsfiddle.net/gh/get/jquery/1.9.1/igniteuisamples/jsfiddle-samples/tree/master/EN/HtmlSamples/scheduler/subject-indicators/)
If there are less than 11, it works correctly but if not it shows the following error:
Thanks for your attention.
Best regards!