Overcoming Accessibility Problems in MQL5 Trading Tools (Part III): Bidirectional Speech Communication Between a Trader and an Expert Advisor - https://www.mql5.com/en/articles/21533
MQL5 Wizard Techniques You should know (Part 86): Speeding Up Data Access with a Sparse Table for a Custom Trailing Class - https://www.mql5.com/en/articles/22136