Rated 4 out of 5 stars

yazan: Stefan tarih: Eyl. 11, 2022 ·

Nice idea, but the icon in the vertical bar doesn't match the design of the other icons and therefore looks very odd.

This review is for a previous version of the add-on (1.2.0). 

yazan: Florent Tassy (Geliştirici) tarih: Eyl. 11, 2022 ·

Thank you for the nice rating :-)

Regarding spaces toolbar icon, you can simply remove it from add-ons preferences if you prefer. If you do so, you can still open a tab dedicated to WhatsApp by right-clicking on the mail toolbar icon ⇾ Open a WhatsApp Web tab.

Otherwise, please give a try to the new 1.3.0 version, it is now possible to change the icon style from the add-on preferences menu. It won't match your exact Thunderbird style, but should look less odd ;-)