--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -1906,19 +1906,20 @@ function URLBarSetURI(aURI) {
 
     value = aURI.spec;
     if (value == "about:blank") {
       // Replace "about:blank" with an empty string
       // only if there's no opener (bug 370555).
       if (!content.opener)
         value = "";
     } else {
-      // try to decode as UTF-8
+      // try to decode as UTF-8 (escaping whitespace so that it doesn't
+      // get eaten away by the location bar; cf. bug 410726)
       try {
-        value = decodeURI(value).replace(/%/g, "%25");
+        value = decodeURI(value).replace(/[%\r\n\t]/g, encodeURI);
       } catch(e) {}
 
       state = "valid";
     }
   }
 
   gURLBar.value = value;
   SetPageProxyState(state);