diff --git a/config.def.h b/config.def.h
index 2db320e..2bf8b1c 100644
--- a/config.def.h
+++ b/config.def.h
@@ -35,8 +35,9 @@ static const Rule rules[] = {
 	 *	WM_CLASS(STRING) = instance, class
 	 *	WM_NAME(STRING) = title
 	 */
-	/* class      instance    title                 tags mask     isfloating   monitor */
-    {"firefox",   "Toolkit",  "Picture-in-Picture", -1,           1,           -1},
+	/* class        instance       title                 tags mask     isfloating   monitor */
+    {"firefox",     "Toolkit",     "Picture-in-Picture", -1,           1,           -1},
+    {"stalonetray", "stalonetray", "stalonetray",        -1,           1,           -1},
 };
 
 /* layout(s) */