[lrs]

It's a little tricky b/c you're screenshot has the inspector settings in German. But the line demarcates where you're page breaks are according to page setup since you are now set to multiple of printer sheets, I think. I actually was coming back to this forum to resolve an issue around fitting to one page and saw this and wanted to offer a little help. You can clearly see though your diagram is 1000px by the ruler.

It can be sort of trial and error. Sometimes I just use the "auto-adjust canvas size" and then create either a PDF or JPG and crop that file b/c it's easier to manage. Also, I do that b/c sometimes at client's sites I can't make sense of their printer settings or the tray for 11x17 and all that.