Could be some hoarding to some extent, could be some OCD. It could also be she’s got the wrong furniture that, regardless of arrangement, just will never seem right to her. I had a terrible shortage of horizontal space in a not very large room. I resolved it by converting 5.5 banker’s boxes worth of paperback books to epub files for my nook. I dunno, maybe new and different window treatments will solve her problem or a different colour paint.
When I was a kid, my mother would rearrange the living room furniture whenever she was sick, to demonstrate that “Mom doesn’t get sick days”. :rolleyes: 
One day, I came home from school and the living room furniture had been rearranged, and I asked her if she was sick.
She didn’t get upset about it (to my surprise; maybe it was because she wasn’t) and she also stopped doing that kind of thing - when she was sick, anyway.
My back is not a wonder of nature, and I told her a long time ago, two simple rules:
Before any rearrangement of heavy furniture, you must plot it out on a graph, and
After any rearrangement, we’ll wait 6 months before the next one.
We have been married since March of 1979.