diff --git a/phpBB/styles/prosilver/composer.json b/phpBB/styles/prosilver/composer.json
index 25456c6d55..51024f2285 100644
--- a/phpBB/styles/prosilver/composer.json
+++ b/phpBB/styles/prosilver/composer.json
@@ -20,6 +20,7 @@
 	},
 	"extra": {
 		"display-name": "prosilver",
-		"phpbb-version": "4.0.0-a1-dev"
+		"phpbb-version": "4.0.0-a1-dev",
+		"parent-style":  ""
 	}
 }