diff --git a/config.h b/config.h
index 624c0bf..c6dc01f 100644
--- a/config.h
+++ b/config.h
@@ -167,8 +167,8 @@ static const Rule rules[] = {
     RULE(.wintype = WTYPE "SPLASH", .isfloating = 1)
     RULE(.role = "pop-up", .isfloating = 1)
     RULE(.class = "St", .isfloating = 0)
-    RULE(.class = "Thunderbird", .monitor = 1)
-    RULE(.class = "Ferdium", .monitor = 1)
+    RULE(.class = "Ferdium", .monitor = 1 .tags = 1 << 1)
+    RULE(.class = "Thunderbird", .monitor = 1, .tags = 1 << 2)
     RULE(.instance = "gcr-prompter", .floatpos = "50% 50% 308W 214H")
     RULE(.instance = "sphelp", .scratchkey = 'h', .isfloating = 1, .floatpos = "50% 50% 40% 80%")
     RULE(.instance = "spcalc", .scratchkey = 'c', .isfloating = 1, .floatpos = "50% 50% 40% 80%")