diff --git a/layout/base/nsRefreshDriver.h b/layout/base/nsRefreshDriver.h
index e13dc30637f7..50320b839c1a 100644
--- a/layout/base/nsRefreshDriver.h
+++ b/layout/base/nsRefreshDriver.h
@@ -63,7 +63,7 @@ public:
   // nsISupports will already have methods with the correct signature.
   //
   // The refresh driver does NOT hold references to refresh observers
-  // except while it is notifying them.  
+  // except while it is notifying them.
   NS_IMETHOD_(nsrefcnt) AddRef(void) = 0;
   NS_IMETHOD_(nsrefcnt) Release(void) = 0;