User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:79.0) Gecko/20100101 Firefox/79.0

Steps to reproduce:

Pick an email
goto File Print or Print Preview and click

Actual results:

A Blank window pops up

Expected results:

Print - Should have popped up the Print window

Print Preview - Should have popped up the print preview of the email

There seems to be a lot of problems lately with the Print options
Must be someone with "smarts" to fix this once and for all.

Thanks. This one was small cause big effect - missing object reference caused by toolkit restructuring. Already fixed in bug 1654548, will land everywhere soon.