A "Firefox" bug... Interesting. What happens in other browsers? What happens when you try preview a doc? I have no issues with preview. see screenshot Are you in Dev or Beta?

I'm using dev I have no problem previewing a doc chrome and other browser works

I'm making a barcode app. When I'm trying to print it, the preview just shows a black rectangle on my barcode. My barcode is a svg The code basically adds that svg to an empty print window.