I have just installed Photoshop Elements and Premium Elements in a system with the level 12. A HP laptop running Windows 10 and using an external monitor for photographic correction.
I go to Organizer and it just flashes and flashes organizer screens, I have to hit control alternate delete, get the task menu, Organizer stabilizes and then I delete the task menu and usually I can use the organizer. I didn't have to do this dance with Elements 12.
Also, did the designers of Organizedr 15 really use this? I'm not happy at all with it, but having done the conversion on my level 12 organizer, it looks to me like I"m comminted to 15. I'm not a happy camper for the first time in well over a decade with multiple levels of Elements and Elements Premier.
Also, did the designers of Organizedr 15 really use this?
There is no doubt that Adobe has not tested the software on YOUR own hardware.
The symptoms you are describing are pointing to a hardware driver problem, probably your dispaly driver used for the external monitor.
Updating the driver from the HP site might help.
...but having done the conversion on my level 12 organizer, it looks to me like I"m comminted to 15.
No, it seems you still have your version 12 working on your computer?
Then, PSE12 organizer should work as before; it will open the last catalog automatically (that catalog has been renamed with a -1 suffix to allow keeping the original name in the copy in the PSE15 format).
You can still work in PSE12 with that previous catalog and simply import the newer files.