There was a change when I removed the stepped column which I guess isn't reflected in the Wiki. 
 
Change the step column in the activities table for both activities from 0 to 1. If all activities have step=0, the task is sequential, i.e. one activity must be completed before the next is unlocked. 
		
	
		
		
		
		
		
		
		
		
		
	
		
		
	
	
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