Ends of curved line won't extend in Keynote
I inserted a curved line into a slide, and tried to extend the end points to desired points, but the shape is unresponsive. When I place the cursor on the end point, the edit selection indicator (the tiny vertical line with two left & right arrow heads pointing away) does pop up, but I can not move the curve end point no matter which button or trackpad feature I hold down simultaneously. Of interest the middle of the curve, green point, which controls the curviture of the line does respond. The entire shape shifts to the side and distorts its curviture if any end point or midpoint is attempted to drag into a new location. Also when one end point is attempted (to no avil) and the other, the whole curved line disappears altogether (hidden in the background behind text boxes), and the coordinate window for the last point attempted greys out. When the curve is just inserted fresh, the coordinate windows on both start and end points are accessible and end points can be moved by adjusting the x & y coordinate up and down arrows. Any ideas?
MacBook Pro, OS X Mavericks (10.9), Keynote 6.0