Mission accomplished...a fairly quick and easy repair. I removed the lower inspection panel on the door. Using an inspection mirror and light, I found that window jumped out from the front side U-shaped channel guide (proper name?). I was able to get the window back in place as normal, and the window works just as well as it did prior to this mishap. I will have to carefully watch it to see if this repeats itself. I recently served as chauffeur for my wife on some errands; I recall her slamming the door with some vigor. I suspect that is when the problem surfaced. I am thankful to not have to get involved with a regulator repair. The picture supplied in this thread was a nice help. Thanks to all for your guidance and support.
