After many requests to allow one to "Print a View", we added the ability to set a Print Area in Canvas since Canvas version 9. Everything else is the same as in previous versions of Canvas. "Show Print Area" should not be available until a "Print Area" is set.
If you want to see the maximum print area allowed by the selected printer, use Show Page Breaks instead of using Set Print Area, which will override this. Show Page Breaks will display a magenta rectangle outlining the printable area determined by the selected printer.
If you choose TILE from Page Setup while Show Page Breaks is active you will see the tiles in the document. Choosing "From Printer" in Document Setup will also adjust the printable area of the Canvas page to match that of the selected printer.