Opens a new chart with the specified symbol and period. The command is added to chart message queue and executed only after all previous commands have been processed.
[in] Chart symbol. NULL means the symbol of the current chart (the Expert Advisor is attached to).
[in] Chart period (timeframe). Can be one of the ENUM_TIMEFRAMES values. 0 means the current chart period.
The maximum possible number of simultaneously open charts in the terminal can't exceed the CHARTS_MAX value.