
The idea of this indicator is based on the hypothesis that the unusual change of the price (the exit of volatility limits) is accompanied by a backward motion.
In the trading, there are many examples of such behavior, for example, there is the story of Lehman Bros, Flash Crash, and others.
The signal appears when the limits of the gray cloud volatility are exceeded. In this case, the backlash reaction can be expected. In this situation, the ledge of the histogram is painted in the appropriate color.
For the application of this indicator one needs the classes of the SmoothAlgorithms.mqh library. It should be copied in the folder of catalog_data_terminal\MQL5\Include. A detailed description of how to work with the classes can be found in the article “The price series averaging without additional buffers for temporary calculations”.