Integrating the messages in the historic tester tab is a very good idea!
I also like the idea of multiple instances

When working on the dialog anyway, could you please consider presetting an initial timeframe that is applied on the historical chart upon opening at the start of the tester run?
At the moment the charts are opening on the tick, which slows the testing down a lot when having IChartObjects on the chart.
If you don't want to add a new field to select a timeframe, you maybe could preset the timeframe to something other than ticks? (My proposal: at minimum FIVE_MINS or above).
Thanks a lot for considering.
Best, RR.