Sorry, there is a bug when the scaling is not 100%. There are several bug reports on file with the developers and we are waiting to hear about a fix. I'm not currently aware of an about:config workaround, although perhaps someone else knows of one.

Thanks for confirming the bug.

When printing to small media, such as address labels, Firefox will not allow the user to zero the top and bottom margins. For labels that are only one inch high there is no printable area because the margins take up all of the space. But the margins are frozen for that media size, so we have to use a different browser.

When the print job is larger than 8 1/2 x 11, the text does not scale down to the media size. It just gets cropped off. This cropping behavior did not happen in the prior Print Preview in Firefox... or the "classic" Print Preview (which is not as pretty, but worked very well).

You can go into about:config, search for print.tab_modal.enabled and set it to false to get the "classic" Print Preview back. This workaround is what I have to do and is necessary.

My two cents: businesses and thousands of employees rely on Firefox. A sure way to create distrust of an app is to insufficently test a new feature and release it. We trusted Firefox more than Chrome. But Firefox has done this twice now with their Print Preview. (To be fair, Chrome did this at least three times with their Print Preview, which is why we trusted Firefox more.) I could care less what Microsoft browsers do... I won't use them.

My other two cents: changing a program just to make it prettier is not a good enough reason to make changes. Function needs to be improved as well, and certainly not degraded.

Here is the bug I'm referring to:

There was a major change to the layout code involving seven parts, and one of those causes cropped printing with "Fit to page width"/"Shrink to fit" or any scaling other than 100%. This seems not to have been detected in beta testing.

The value of print.tab_modal.enabled does not matter for this bug because it affects how the page is laid out for printing either way. You can see the bug here: https://www.jeffersonscher.com/res/widepage.html

Regarding margins:

You can double-check the margins for your label printer this way:

(A) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

(B) In the search box in the page, type or paste print_margin and pause while the list is filtered

Firefox should display top, left, right, and bottom margins for all of the printers you have used. If you are using inch measurements, the values typically would be in the range of 0.2 to 0.5 (often with numerous additional digits).

(C) If you need to fix a value, double-click that row to display an editing field, and change the value to 0.5 or whatever you like, then press Enter or click the blue check mark button to save the change.

(D) In the search box in the page, type or paste print_edge and pause while the list is filtered

Firefox should display top, left, right, and bottom "unprintable area" values for all of the printers you have used. This typically would be a number between 0 and 20 (20 is 0.2 inches).

(E) If you need to fix a value, double-click that row to display an editing field, and change the value to 20 or whatever you like, then press Enter or click the blue check mark button to save the change.

This about:config workaround is very specific and very useful. Thank you for posting this!