Hi Lou,
I don't know what are the exactly event labels you are using in your real code. In this example, replacing
Graphics[{RandomChoice[{Green, Red}], Disk[]}, ImageSize -> 10]
with
Style["\[FilledCircle]", RandomChoice[{Red, Green}]]
will much help the load of renderer. Could you give it a try?
Also, try to set the ChartElementFunction to be "Candlestick":
ChartElementFunction -> "Candlestick"
To see if that helps.
