diff --git a/xpfe/global/resources/content/commonDialog.js b/xpfe/global/resources/content/commonDialog.js
index 3fa4a48efd07..ed2df9b1f128 100644
--- a/xpfe/global/resources/content/commonDialog.js
+++ b/xpfe/global/resources/content/commonDialog.js
@@ -103,8 +103,17 @@ function setLabelForNode(aNode, aLabel, aIsLabelFlag)
 
 function commonDialogOnLoad()
 {
-  // set the document title
-  document.title = gCommonDialogParam.GetString(12);
+  // Set the document title. On Mac, we only care about URI's.
+  if (/Mac/.test(navigator.platform)) {
+    var titleString = gCommonDialogParam.GetString(12);
+    if (/^\w+:\/\/\w/.test(titleString)) {
+      setElementText("info.title", titleString, true);
+      unHideElementById("info.title"); // Show URI inside dialog.
+    }
+  }
+  else {
+    document.title = gCommonDialogParam.GetString(12);
+  }
 
   // set the number of command buttons
   var nButtons = gCommonDialogParam.GetInt(2);
diff --git a/xpfe/global/resources/content/commonDialog.xul b/xpfe/global/resources/content/commonDialog.xul
index db12e8d4cc2a..e709cfa47453 100644
--- a/xpfe/global/resources/content/commonDialog.xul
+++ b/xpfe/global/resources/content/commonDialog.xul
@@ -21,6 +21,8 @@
     </hbox>
     
     <vbox flex="1" style="max-width: 45em;">
+      <!-- title -->
+      <description id="info.title" class="header" hidden="true"/>
       <!-- text -->
       <description id="info.header" class="header"/>
       <vbox id="info.box"/>