It would appear that by default LR is going to launch the most recent version of PS you have installed.
The workaround that you have found would be the solution for running an older version of PS, short of uninstalling PS 2014.
@ManiacJoe your explanation makes perfect sense. When CC releases a new version of Photoshop, they release both CC and CC 2014. I probably installed PSCC then PSCC 2014, making it the most recent version installed. I didn't notice the problem until now because either I have been running PSCC continuously or because I launch PSCC before launching LR. It may also be that I didn't notice the DIFFERENCE between PSCC and PSCC 2014 until I reconfigured my workspace in PSCC. I think the correct solution (for me) would be to uninstall PSCC 2014 because I never use it. Thank you for your help!
To prevent this problem from happening in the future, I uninstalled Photoshop CC 2014. I did this using the Creative Cloud Desktop app, which not only uninstalls the program on Windows but also changes its status on the Adobe server.
After the uninstall, the folder C:\Program Files\Adobe\Adobe Photoshop CC 2014 was empty except for the plugins directory. So far, so good.
I launched Lightroom and checked the External Editing preferences. It now shows this (good):
I selected a file in Lightroom and did Photo -> Edit in -> Edit in Adobe Photoshop CC (ctrl-E). Photoshop CC launches (good).
But now the problem: The file does not open!
I repeated the experiment with Photoshop CC already running. Same result: the Photoshop window comes forward to the top of the desktop window stack, but the file does not open.
It looks like Lightroom is still sending the file down the wrong pipe because it's not getting to Photoshop.
Any idea of what's happening here? Meanwhile, I will reboot Windows and see if that clears up the problem.
Rebooting Windows did not solve the problem. ctrl-E in Lightroom continues to send files into the void.
I keep adding replies because the forum is not allowing me to edit my previous posts.
I discovered that ctrl-E works for psd's, tifs, and jpegs, but not for raw files. ctrl-E constently fails to send the file to Photoshop CC for edit. I have tried with a variety of dng's, nefs, and cr2's and the result is always the same: the file simply does not show up in Photoshop CC (although the Photoshop window comes to the fore, as if expecting to receive a file).