diff --git a/browser/base/content/browser.xul b/browser/base/content/browser.xul
index ed4d07a746a9..1aa504ef4d75 100644
--- a/browser/base/content/browser.xul
+++ b/browser/base/content/browser.xul
@@ -332,7 +332,8 @@
 
     <menupopup id="placesContext"/>
 
-    <panel id="notification-popup" type="arrow" position="after_start" noautofocus="true" hidden="true"/>
+    <panel id="notification-popup" type="arrow" position="after_start"
+           noautofocus="true" hidden="true" orient="vertical"/>
 
     <!-- Popup for site identity information -->
     <panel id="identity-popup" position="after_start" hidden="true" noautofocus="true"
diff --git a/toolkit/content/widgets/notification.xml b/toolkit/content/widgets/notification.xml
index 3ed3c6e2cc8b..6f2d2df1535c 100644
--- a/toolkit/content/widgets/notification.xml
+++ b/toolkit/content/widgets/notification.xml
@@ -423,7 +423,7 @@
     <content align="start">
       <xul:image class="popup-notification-icon"
                  xbl:inherits="popupid"/>
-      <xul:vbox>
+      <xul:vbox flex="1">
         <xul:description class="popup-notification-description"
                          xbl:inherits="value=label"/>
         <xul:spacer flex="1"/>