So this is getting even more strange!
I thought I would post screenshots. When I used the Ubuntu screenshot app it captured what should have been on the screen not what was on the screen at the moment I took the shot. Taking the screenshot caused the screen to refresh and display correctly. I had previously found that I could usually correct the display by clicking outside the window having issues.
Consequently I have taken pictures with my phone. The first is a settings page displaying correctly. Note the content of the printer window.
- 20B9DFC1-0DC1-43F7-812E-6D5470FFCA4F.jpeg (69.21 KiB) Viewed 2030 times
The second is after I clicked the back arrow and dragged my mouse pointer down the left hand side of the screen. You can now see the higher level menu items on the left but still the printer window on the right.
- A6398A0A-8684-4287-B1DB-83E3C16DE5AE.jpeg (70.63 KiB) Viewed 2030 times
In summary some bits of the window display correctly and others don’t. In the file manager you can get an apparently empty folder displayed when it’s full of files. If you scroll in file manager it gets really weird. The Conky window on the right seems to display perfectly. The SpiderOak interface is also unaffected. Firefox gets scrambled too.