diff --git a/sway/behaviours b/sway/behaviours
index 6639bc5cd..0f6262f64 100644
--- a/sway/behaviours
+++ b/sway/behaviours
@@ -13,8 +13,9 @@ assign [class="Mattermost"] 1
 assign [app_id="Mattermost"] 1
 assign [class="Rocket.Chat"] 1
 assign [app_id="Rocket.Chat"] 1
-# 2 - Mail
+# 2 - Mail - Thunderbird seems to change the way it identifies with every update!
 assign [class="Thunderbird"] 2
+assign [class="thunderbird"] 2
 assign [class="thunderbird-default"] 2
 assign [app_id="thunderbird"] 2
 # 3 - Secondary Browser