I find it very strange that objects become invisible when you place them next to the page.
I do this sometimes temporarily. You don't even see the outline which means you can't even see if there is anything at all.
One time I sort of "lost" a picture frame and wondered if it was put there by accident. No way to see.
This way you also can;t use the area as a temporary space to put some objects you're experimenting with and such.