Add control point along spline

[Elenesski]

Hi,
I watched the tutorial videos but cannot find where in the video or documentation it describes how to add a control point in the middle of a spline.  How do you add a control point along an existing spline?

Thanks.

1. Select the Spline.
   
2. Click "Draw Spline" in the scene view.
   
3. When you move your mouse over the pop ups to the right, you'll notice "Hold [Ctrl] to add Control Points" at the bottom of the scene window.