I cannot find the Exit Sketch icon in the the Sketch tollbar or anywhere else.  I have gone into Tools>Options, System Option Tab, General Category and checked the Enable Confirmation Corner box.  Apparently because I am unable to exit sketch, when I go into the  Features toolbar several icons such as Revolved Boss/Base, Swept Boss/Base, Extruded Cut, Hole Wizard, Revolved Cut and others are grayed out.