Thanks, Geoff.  Selecting Automation | Pan in the drop-down displayed a dotted line.  Double-clicking on that line with the Smart Tool created nodes.  Using the Smart tool, I could drag one up and one down to create a diagonal line.  That solved the problem, so thanks very much!
 
I still do not understand why the line tool doesn't work since it would be an obvious and simple solution; however, your method works perfectly.
 
Thanks again and sorry I made this so much trouble.  I owe you a drink or two when I see you.
 

Konrad,
 
I don't normally use the line tool. It's like free hand draw. It's mainly used by Control Surfaces for automation or when using touch screen to write track automation. It quantizes and uses curves between nodes etc to create really nice automation envelopes. I pretty much NEVER draw these in with the mouse. I use my AlphaTrack or my touch screen to create them when I want them.
 
I do the great majority of my automation with my mouse though. I just use it with the smart tool. I don't select the line tool. I click and drag nodes at will.
 
When you have a dotted line it is only because you do not have an automation node at the end of the project. Just add one at the end, right click the line and choose Linear to draw the line in.
 
When using a CS to add automation, you can often end up with the dotted lines. Dotted lines are ok as long as you play the project from the beginning, but if you stop the project with the volume set at 50% and then move the now time to a dotted line at 20%, it will NOT pick up this value. Only the solid lines are enforced automation. The dotted line shows where the value would be extended out from the last automation node.

Cool.  I use control surface automation all the time but never really stopped to think about the dotted line behavior.  I see what you mean: the console won't search back for the last value.

hey konrad - 
just noticed you're still on x1d - the line tool doesn't work for automation or midi cc's in prv (does work for notes though)... it was fixed in x2.   

Good to know, swamptooth.  Thanks for letting me know.
 
In this case, what I was trying to do was draw automation in the track view.  I think I have a way to do it now, but not with the line tool.