--- a/suite/common/tests/browser/browser_bug510890.js
+++ b/suite/common/tests/browser/browser_bug510890.js
@@ -150,17 +150,17 @@ function test() {
         // cleanup & return
         executeSoon(recCallback);
         return;
       }
       // hack to force window to be considered a popup (toolbar=no didn't work)
       let winData = windowsToOpen.shift();
       let settings = "chrome,dialog=no," +
                      (winData.isPopup ? "all=no" : "all");
-      let url = "http://window" + windowsToOpen.length + ".example.com";
+      let url = "http://example.com/?window=" + windowsToOpen.length;
       let window = openDialog(location, "_blank", settings, url);
       window.addEventListener("load", function(aEvent) {
         window.gBrowser.addEventListener("load", function(aEvent) {
           // the window _should_ have state with a tab of url, but it doesn't
           // always happend before window.close(). addTab ensure we don't treat
           // this window as a stateless window
           window.gBrowser.addTab();
           window.gBrowser.removeEventListener("load", arguments.callee, true);