diff --git a/calendar/lightning/content/lightning-preferences.xul b/calendar/lightning/content/lightning-preferences.xul
index 56aa9a679150..180c54fe63e8 100644
--- a/calendar/lightning/content/lightning-preferences.xul
+++ b/calendar/lightning/content/lightning-preferences.xul
@@ -43,8 +43,6 @@
     <!ENTITY % dtd2 SYSTEM "chrome://calendar/locale/global.dtd" > %dtd2;
 ]>
 
-<?xml-stylesheet href="chrome://lightning/skin/lightning.css"?>
-
 <overlay id="LightningPaneOverlay"
          xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
 
diff --git a/calendar/lightning/content/messenger-overlay-preferences.xul b/calendar/lightning/content/messenger-overlay-preferences.xul
index e79c6df01bc9..9e8ee379fae0 100644
--- a/calendar/lightning/content/messenger-overlay-preferences.xul
+++ b/calendar/lightning/content/messenger-overlay-preferences.xul
@@ -39,6 +39,8 @@
 
 <!DOCTYPE overlay SYSTEM "chrome://lightning/locale/lightning.dtd" >
 
+<?xml-stylesheet href="chrome://lightning/skin/lightning.css"?>
+
 <overlay xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
 
 <prefwindow id="MailPreferences">