Thunderbird Scale change

Thunderbird scale configuration

1) Go to Options (General)>Scroll down to bottom of page and click Config Editor...
2) Accept risks and continue.
3) Search for the value layout.css.devPixelsPerPx
4) right click on the value and click modify
5) set the value to change the scale of Thunderbird (default value is -1.00), recommended values are: 1, 1.25, 1.5 or 1.75