diff --git a/mozilla/browser/base/content/aboutDialog.xul b/mozilla/browser/base/content/aboutDialog.xul
index 87cfdc9f53a..435955ac55d 100644
--- a/mozilla/browser/base/content/aboutDialog.xul
+++ b/mozilla/browser/base/content/aboutDialog.xul
@@ -53,6 +53,7 @@
 <dialog xmlns:html="http://www.w3.org/1999/xhtml"
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
         id="aboutDialog"
+        windowtype="Browser:About"
         onload="init(event);" onunload="uninit(event);"
 #ifdef XP_MACOSX
         buttons="extra2"
diff --git a/mozilla/browser/base/content/utilityOverlay.js b/mozilla/browser/base/content/utilityOverlay.js
index 5418021dcc8..afe14b136e7 100644
--- a/mozilla/browser/base/content/utilityOverlay.js
+++ b/mozilla/browser/base/content/utilityOverlay.js
@@ -397,8 +397,17 @@ function isBidiEnabled() {
 function openAboutDialog()
 {
 #ifdef XP_MACOSX
-  // XXXmano: define minimizable=no although it does nothing on OS X (see Bug 287162); remove this comment once Bug 287162 is fixed...
-  window.open("chrome://browser/content/aboutDialog.xul", "About", "centerscreen,chrome,resizable=no, minimizable=no");
+  var wm = Components.classes["@mozilla.org/appshell/window-mediator;1"]
+                     .getService(Components.interfaces.nsIWindowMediator);
+  var win = wm.getMostRecentWindow("Browser:About");
+  if (win)
+    win.focus();
+  else {
+    // XXXmano: define minimizable=no although it does nothing on OS X
+    // (see Bug 287162); remove this comment once Bug 287162 is fixed...
+    window.open("chrome://browser/content/aboutDialog.xul", "About",
+                "centerscreen,chrome,resizable=no, minimizable=no");
+  }
 #else
   window.openDialog("chrome://browser/content/aboutDialog.xul", "About", "modal,centerscreen,chrome,resizable=no");
 #endif