Curved Lines with an Arrow on the End

I cannot seem to get a curved line with an arrow on one end.  I am re-creating a course from a PowerPoint course in Storyline 360 (just line the trigger functionality better), and when I draw a curved line and go to Format Shape; Line Style, the functionality is greyed out.  This seems wrong.  Why would we not be able to do this?

Also, the curved line shape seems to add a little extra curve to the ends, see attached pictures.  Why is this?  I guess I could have used the arc instead for one of the shapes I need?  In curve2.png you can see when I start to draw the curve, the first portion is straight, and as soon as I click escape to finish after making the curve, it adds a more "s" curve to it, see curve2_magnified.png.

Finally, is there a way to edit curves after they have been completed?