diff --git a/config.def.h b/config.def.h
index 82f9474..3003bb9 100644
--- a/config.def.h
+++ b/config.def.h
@@ -39,10 +39,12 @@ static const Rule           rules[] = {
      *	WM_CLASS(STRING) = instance, class
      *	WM_NAME(STRING) = title
      */
-    /* class                instance    title       tags mask       isfloating      monitor */
-    {"firefox",             NULL,       NULL,       1 << 0,         0,              -1},
-    {"thunderbird",         NULL,       NULL,       1 << 6,         0,              -1},
-    {"ManagerDesktop",      NULL,       NULL,       1 << 7,         0,              -1},
+    /* class                    instance    title       tags mask       isfloating      monitor */
+    {"firefox",                 NULL,       NULL,       1 << 0,         0,              -1},
+    {"thunderbird",             NULL,       NULL,       1 << 6,         0,              -1},
+    {"org.mozilla.Thunderbird", NULL,       NULL,       1 << 6,         0,              -1},
+    {"ManagerDesktop",          NULL,       NULL,       1 << 7,         0,              -1},
+    {"Manager",                 NULL,       NULL,       1 << 7,         0,              -1},
 };
 
 /* layout(s) */