OK, I think I solved my mystery.  When I made the changes, Vue went right back to not working again.  No personalized scene.

I discovered you have to have the box "Create empty scene on startup" checked after you personalize your scene and click the "Set default scene."  I would have thought this one should be unchecked or else you'd get a default scene rather than your own personalized scene.

But I got it to work using the above method, however, like in Gill's case, "Render to screen" is the only option that doesn't stick.