Restore the page overlay display in the print dialog.
I previous version of InDesign and the initial releases of InDesign 2017, you could see quite clearly what would print on the selected sheet size. In the latest update as of Aug 2017, if I change a sheet from letter to legal that has been printed previously, letter is still selected in the dialog, but due to the preview sheet being legal and cannot see that there is a size mismatch without going through the individual dialogs. For reference, the portion of the document that would not be within the printable region showed as a different shade of grey, whereas the entire preview now shows white.
Corrected in Version 13.0 release.