I am not sure if this was always the case but it seems new to me, when I hide all layers in an Illustrator CC 2020 document, the canvas outside the art board is white ( kind of like outline )
I have toggled GPU Preview which solves it but as soon as I turn the layer on & off again , it reverts to white.
I have tried Overprint Preview, I have tried View > Hide / Show Art boards
There is a chance it has always been like this, but in the years hiding all layers , I have never noticed it. I feel that I may have hit a shortcut that did some obscure action which I cannot revert.
Attached is a screen shot of a new document with a single layer On & then Off
UI Interface is not the issue , nor is Outline.
Appreciate any help , thank you