Well, almost blank. It has weather and a volume icon.
This is the second time I’ve lost my customisations, so my first question is how can I make a backup?
Re the problem itself, it seems to occur when I was swapping my secondary monitor for a new model. I hot-swapped HDMI and the desktop went completely blank - background image only. No panel or menus
On reboot my top panel was changed to lose my customisations. However my bottom panel and dock (set to left side) were all intact as I had customised them, but top panel is empty.
How can this be made more stable?