CancelTimer activity expects "activity-" prefix

Hi,

I did notice that the QuartzTimers-example fails within the CancelWorkflow example.
If you execute the example the string "Should not be executed" will be written to the console although the timer should have been cancelled.
After debugging around I found out, that the CancelTimer activity tries to get the blocking activity by comparing it to it's activity id. Unfortunately the activityId of the blocking activity is "activity-timer-1" although the WithId method while setting up the timer specifies "timer-1" as it's id.
So when cancelling with "timer-1" the activity is not found and the cancellation silently fails.
Changing the call to CancelTimer("activity-timer-1") fixes the example.
Is this by design so should we prepend the activityId with "activity-" when using the CancelTimer activity or is there a bug somewhere?

Regards
Joscha