Ans 1. The answer to your 1st question is simple. Unfortunately you cant. Out of the box Excel doesn't support deselection via clicking for a second time. (Surprising how M'Soft didn't think about this)
You have some external 3rd party plugins (Kutools for example) which does allow you to achieve it.
A workaround is writing a VBA script for the same, however that is kind of going over the edge.
Ans 2. Well I don't have excel 2013 so I can't help you with that one unfortunately. In 2010 it seemed to work pretty normal.