Set bar color outside of OnBarUpdate()

[supernatural]

Hello,
I have to modify a bar's color and back color outside of OnBarUpdate() in a different thread as I get the data I use to color the bars asynchronously. Let's say I want to modify the color of bar N (bar index starting at 0 for first bar). I do BarColorSeries[CurrentBar - N] = some color. The problem is that, depending on the volatility and the rate of creation of new bars, it tends to miss bar N and modify the color of a nearby bar. How can I get it to always accurately modify the color of the target bar under these conditions?
Thanks

[NinjaTrader_Bertrand]

supernatural, this would unfortunately not be supported outside of OnBarUpdate() context, as you could run into the race / timing conditions you experienced, as it's really tied to the bars series / index.