weird gray non-page non-printing area

[miconian]

I was playing around in print preview, and I decided to add a page to the document. I tried to do this by copying a range, and then pasting it down below the bottom page.

Bizarrely, the range does now appear where the new page should be. But the page itself is not there. The range is on a gray background, as if to suggest that they are not really on a page at all.

Changing back to normal view or resetting the page breaks doesn't seem to help.

Surely I'm missing something obvious here?

thanks!