Couple of questions...

[DRG]

1. Undo only works if you are not observed by the enemy. ( that is "SP101" that goes back decades) Therefore you were under observation and in cases like that, there is no "oops" undo.
   
2. When smoke/dust is cleared to view the map it stays that way until a unit is moved or a unit fires that generate more smoke/dust. That is the way it works. It does not re-appear until more is generated after pressing clear and if smoke/dust is shown in one hex it shows on every hex that has it. That's been that way for years as well