diff --git a/auklib/auklib.go b/auklib/auklib.go
index bc6c294..994c573 100644
--- a/auklib/auklib.go
+++ b/auklib/auklib.go
@@ -47,6 +47,7 @@ func UniqueStrings(slice []string) []string {
 	var unique []string
 	m := make(map[string]bool)
 	for _, s := range slice {
+		s = strings.ToLower(s)
 		if !m[s] {
 			m[s] = true
 			unique = append(unique, s)
@@ -54,12 +55,3 @@ func UniqueStrings(slice []string) []string {
 	}
 	return unique
 }
-
-// ToLowerSlice lowers capitalization of every string in the given slice.
-func ToLowerSlice(slice []string) []string {
-	var out []string
-	for _, s := range slice {
-		out = append(out, strings.ToLower(s))
-	}
-	return out
-}
diff --git a/window/window.go b/window/window.go
index fcac382..67cccd7 100644
--- a/window/window.go
+++ b/window/window.go
@@ -220,7 +220,7 @@ func (w *Window) UnmarshalJSON(b []byte) error {
 	if len(conv.Labels) == 0 {
 		return fmt.Errorf("window(%s): window must have minimum of one label (found: %d)", w.Name, len(conv.Labels))
 	}
-	w.Labels = auklib.UniqueStrings(auklib.ToLowerSlice(conv.Labels))
+	w.Labels = auklib.UniqueStrings(conv.Labels)
 
 	w.Starts = conv.Starts
 	w.Expires = conv.Expires