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

Steps to reproduce:

TB 80.0b1 (32 bit)
Tried to print message.
Tried to do print preview.

Blank screen opens with no text in screen.
I can close the blank screen.

Actual results:

Select either print preview or print on any given message.
Window opens with no text or options in window.
I can close this window.
Tried print and print view from several locations within TB ... all with same results.

Expected results:

In print preview I should have seen a rendering of the message.
In print I should have been given option to select which printer and how many pages to print, etc..

Will be fixed in 80.0b2