diff --git a/util.go b/util.go
index 26131a3ff..bcf90077d 100644
--- a/util.go
+++ b/util.go
@@ -53,7 +53,7 @@ func FilterCustomQuery(u *nurl.URL) *nurl.URL {
 	ux := *u
 	vx := make(nurl.Values)
 	for k, v := range ux.Query() {
-		if len(k) <= 1 || (len(k) > 1 && k[0:2] != "x-") {
+		if len(k) <= 1 || k[0:2] != "x-" {
 			vx[k] = v
 		}
 	}
diff --git a/util_test.go b/util_test.go
index 1ad234473..2e8558d7a 100644
--- a/util_test.go
+++ b/util_test.go
@@ -21,7 +21,7 @@ func TestSuint(t *testing.T) {
 }
 
 func TestFilterCustomQuery(t *testing.T) {
-	n, err := nurl.Parse("foo://host?a=b&x-custom=foo&c=d")
+	n, err := nurl.Parse("foo://host?a=b&x-custom=foo&c=d&ok=y")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -29,4 +29,7 @@ func TestFilterCustomQuery(t *testing.T) {
 	if nx.Get("x-custom") != "" {
 		t.Fatalf("didn't expect x-custom")
 	}
+	if nx.Get("ok") != "y" {
+		t.Fatalf("expected ok=y, got %v", nx.Get("ok"))
+	}
 }