--- a/browser/app/profile/firefox.js
+++ b/browser/app/profile/firefox.js
@@ -1646,8 +1646,10 @@ pref("extensions.formautofill.loglevel",
 // Whether or not to restore a session with lazy-browser tabs.
 pref("browser.sessionstore.restore_tabs_lazily", true);
 
 // Enable safebrowsing v4 tables (suffixed by "-proto") update.
 #ifdef NIGHTLY_BUILD
 pref("urlclassifier.malwareTable", "goog-malware-shavar,goog-unwanted-shavar,goog-malware-proto,goog-unwanted-proto,test-malware-simple,test-unwanted-simple");
 pref("urlclassifier.phishTable", "goog-phish-shavar,goog-phish-proto,test-phish-simple");
 #endif
+
+pref("browser.suppress_first_window_animation", true);

--- a/browser/components/nsBrowserContentHandler.js
+++ b/browser/components/nsBrowserContentHandler.js
@@ -571,17 +571,22 @@ nsBrowserContentHandler.prototype = {
         if (height)
           this.mFeatures += ",height=" + height;
       } catch (e) {
       }
 
       // The global PB Service consumes this flag, so only eat it in per-window
       // PB builds.
       if (PrivateBrowsingUtils.isInTemporaryAutoStartMode) {
-        this.mFeatures = ",private";
+        this.mFeatures += ",private";
+      }
+
+      if (Services.prefs.getBoolPref("browser.suppress_first_window_animation") &&
+          !Services.wm.getMostRecentWindow("navigator:browser")) {
+        this.mFeatures += ",suppressanimation";
       }
     }
 
     return this.mFeatures;
   },
 
   /* nsIContentHandler */