AutoCad 2D :: Add Vertex To End Of Polyline?

problem I am encountering with adding vertices to the ends of polylines in AutoCAD LT 2012:

I typically use the drop down menu that shows up when hovering over the end (or mid) point of a polyline to choose "Add Vertex" to a polyline. If I do this to one end-grip of the polyline, it will add it onto the end of the polyline as an extension (desired and intended effect). If I do it to the other end-grip, it will add the vertex behind the end of the polyline as if I had used the mid-grip to do it (not the desired effect). If I wanted a vertex in the middle of two end points, I would do this procedure using the mid-grip, not the end-grip. One would think that by using an end-grip, it would come off the end, not go into the middle....one would think.

The Question: Is there a short key or quick command to use to guarantee the added vertex will extend from the end of the polyline rather than add one in the middle of the polyline, no matter which end I am trying to extend?