diff --git a/bin/i3-companion b/bin/i3-companion
index a4c0093..8da34c3 100755
--- a/bin/i3-companion
+++ b/bin/i3-companion
@@ -137,6 +137,7 @@ exclusive_apps = {
     "google-chrome",
     "thunderbird",
     "thunderbird-beta",
+    "thunderbird-esr",
 }
 intrusive_apps = {"vbeterm"}