Arduino_LED_Matrix should on() only turn on LED and off all the others?

  1. How is editing the original message a problem? If the issue is that it may seem irrelevant you ask for an information I later added, I specified in #6 that I made this edit after you pointed out some info (the board model) was missing.
  2. How to get the best out of this forum doesen't mention that editing a post for clairification is bad practice.
  3. How is editing a post "spoiling a narrative" ??
  4. The link given is a discussion between people who developed the thing. It is not a readable answer for users discovering this board and this library, the latter not having any proper documentation yet.