Starting Viber with too large resolution

After installing a brand new Ubuntu 18.04 LTS on my computer, I made some adjustments to the font sizes of the operating system in order to make it better suit for my perception. However, I realized that something is wrong after installing Viber on my desktop. The GUI of the Viber application appears so huge that it falls off the resolution of the screen making it completely unusable. After searching on the web, the only solution I found was to start Viber using the terminal with an extra parameter called QT_SCALE_FACTOR. Following is the command which we should run on the terminal to start Viber with a usable scale.

(Note: it is important to set the environmental variable first before invoking the Viber executable as shown.)

QT_SCALE_FACTOR=0.6 /opt/viber/Viber

Reference:

[1] https://askubuntu.com/questions/881679/viber-appears-huge-kubuntu-16-04