diff --git a/framework/yii/debug/assets/main.css b/framework/yii/debug/assets/main.css
index 6cb65dd..7953873 100644
--- a/framework/yii/debug/assets/main.css
+++ b/framework/yii/debug/assets/main.css
@@ -131,6 +131,7 @@ ul.trace {
 	margin: 2px 0 0 0;
 	padding: 0;
 	list-style: none;
+	white-space: normal;
 }
 
 .callout-danger {