Arranger track - event resize?

In Cubase Pro 9.5, after I add the Arranger track to the Project window, I draw in a a block/event to indicate the length of the section/event. However I’m not able to later shorten or lengthen the event length using the normal re-sizing arrows or scissors tool. I have to delete the block/event in the Project window and re-create it. Am I missing something - is this something I can only do in the Arranger Editor window maybe?