After a detailed debug I realized that the CommandEvent documentation completly wrong in latest SDK. CommandEvent eventType numbers are not means what is documented and there is more numbers here. In the API reference there is a small section:
Indicates that a command was started, stopped, suspended, or resumed.
An integer that specifies the type of command operation.
The table above contains incorrect explanation. As I tested it I found event numbers as I described below:
The second thing what you should know is the default command is the Pan (=1) which always starts when any tool reseted. Any tool reseted means this event occures even when (the same) Pan Tool is reseted.
Finally there is an undocumented event number: 500 which comes immediately after MapViewer control created. It always comes with eventType=3 which means "command stopped" - but I don't know which command.
I wonder if I missed or misunderstood something about this?