1. Run this code in debug console:
```
player addEventHandler ["AnimStateChanged", {hint str _this}];
```
2. Move around. Notice that the event handler works.
3. Now run this code:
```
onEachFrame {player setVelocity [0,0,-5]};
```
4. Move around. Event handler doesn't work anymore.
You can try "animDone" and "animChanged" event handlers in step 1. But they work fine regardless of the velocity.