diff --git a/browser/components/sessionstore/test/browser/browser_461634.js b/browser/components/sessionstore/test/browser/browser_461634.js
index 4780acc6c47c..512ee8ab7383 100644
--- a/browser/components/sessionstore/test/browser/browser_461634.js
+++ b/browser/components/sessionstore/test/browser/browser_461634.js
@@ -78,7 +78,7 @@ function test() {
   }
   
   // open a window and add the above closed tab list
-  let newWin = open(location, "", "chrome,all");
+  let newWin = openDialog(location, "", "chrome,all,dialog=no");
   newWin.addEventListener("load", function(aEvent) {
     gPrefService.setIntPref("browser.sessionstore.max_tabs_undo",
                             test_state.windows[0]._closedTabs.length);
diff --git a/browser/components/sessionstore/test/browser/browser_464199.js b/browser/components/sessionstore/test/browser/browser_464199.js
index dd1dd4892ff5..ddc0e0cf9566 100644
--- a/browser/components/sessionstore/test/browser/browser_464199.js
+++ b/browser/components/sessionstore/test/browser/browser_464199.js
@@ -86,7 +86,7 @@ function test() {
     aClosedTabList.filter(function(aData) aData.title == aTitle).length;
   
   // open a window and add the above closed tab list
-  let newWin = open(location, "", "chrome,all");
+  let newWin = openDialog(location, "", "chrome,all,dialog=no");
   newWin.addEventListener("load", function(aEvent) {
     gPrefService.setIntPref("browser.sessionstore.max_tabs_undo",
                             test_state.windows[0]._closedTabs.length);