Radial and Linear Gradient

I've been watching tutorials for gradients in the CR masking section and they're very helpful except that when I attempt to create one the adjustments the lines disappear as soon as I release the left mouse button. I try and create the gradient and then reposition it, but when the lines disapper there is no reference point with which to grab and drag to new position. I assume it's a 1-click setting change, I've not been able to find it. Any suggentions much appreciated.  Camera Raw15.5.1