Custom indicator in strategy tester w/visualization loads history but tick by tick doesn't update values

Hello,

I'm sure this is basic -- can anyone direct me to some information (or the basic solution) as to why a custom indicator which works on the charts does not update tick by tick in the strategy tester?

When the visualization loads, the historical data of the indicator loads and is displayed.  However, when the tick by tick begins the indicator data is not getting updated.  I'm suspecting:

1) Problem with the indicator and because I switch charts so much right now I'm not noticing that live chart tick by tick is not updating

2) Something basic I don't understand about the setup of the strategy tester and custom indicators

I can't test #1 at the moment as the market is closed.

Does anyone have an opinion on what the most likely problem is, a solution, or direction to information that will clarify this for me?

Thanks so much,

-Christian B.