Custom printer dialog

When Preview is aksed to print a document, the printer dialog that it presents shows a picture of what will be printed.

Is there any way to do this in Xojo?

sure, yu add a window, a canvas and draw to the canvas whatever you are going to print.

He meant to show the preview inside the print dialog…

I think you can do that if you use our NSPrintOperationMBS class on macOS to print an existing NSView, which can draw itself to the print panel.