diff --git a/browser/devtools/styleeditor/test/browser_styleeditor_private_perwindowpb.js b/browser/devtools/styleeditor/test/browser_styleeditor_private_perwindowpb.js
index 79eaa96b79ea..58ac1796b727 100644
--- a/browser/devtools/styleeditor/test/browser_styleeditor_private_perwindowpb.js
+++ b/browser/devtools/styleeditor/test/browser_styleeditor_private_perwindowpb.js
@@ -19,23 +19,31 @@ function test() {
       aWindow.gBrowser.selectedBrowser.removeEventListener("load", onLoad, true);
       cache.evictEntries(Ci.nsICache.STORE_ANYWHERE);
       launchStyleEditorChromeFromWindow(aWindow, function(aChrome) {
-        aChrome.addChromeListener({
-          onEditorAdded: function(aChrome, aEditor) {
-            if (aEditor.isLoaded) {
-              checkCache();
-            } else {
-              aEditor.addActionListener({
-                onLoad: checkCache
-              });
-            }
-          }
-        });
+        if (aChrome.isContentAttached) {
+          onEditorAdded(aChrome, aChrome.editors[0]);
+        } else {
+          aChrome.addChromeListener({
+            onEditorAdded: onEditorAdded
+          });
+        }
       });
     }, true);
 
     aWindow.gBrowser.selectedBrowser.loadURI(testURI);
   }
 
+  function onEditorAdded(aChrome, aEditor) {
+    aChrome.removeChromeListener(this);
+
+    if (aEditor.isLoaded) {
+      checkCache();
+    } else {
+      aEditor.addActionListener({
+        onLoad: checkCache
+      });
+    }
+  }
+
   function testOnWindow(options, callback) {
     let win = OpenBrowserWindow(options);
     win.addEventListener("load", function onLoad() {
diff --git a/browser/devtools/styleeditor/test/head.js b/browser/devtools/styleeditor/test/head.js
index d08249dca059..20b32276ff10 100644
--- a/browser/devtools/styleeditor/test/head.js
+++ b/browser/devtools/styleeditor/test/head.js
@@ -29,9 +29,14 @@ function cleanup()
 
 function launchStyleEditorChrome(aCallback, aSheet, aLine, aCol)
 {
-  let target = TargetFactory.forTab(gBrowser.selectedTab);
+  launchStyleEditorChromeFromWindow(window, aCallback, aSheet, aLine, aCol);
+}
 
-  let panel = gDevTools.getPanelForTarget("styleeditor", target);
+function launchStyleEditorChromeFromWindow(aWindow, aCallback, aSheet, aLine, aCol)
+{
+  let target = TargetFactory.forTab(aWindow.gBrowser.selectedTab);
+
+  let panel = aWindow.gDevTools.getPanelForTarget("styleeditor", target);
   if (panel && panel.isReady) {
     gChromeWindow = panel._panelWin;
     gChromeWindow.styleEditorChrome._alwaysDisableAnimations = true;
@@ -40,7 +45,7 @@ function launchStyleEditorChrome(aCallback, aSheet, aLine, aCol)
     }
     aCallback(gChromeWindow.styleEditorChrome);
   } else {
-    let toolbox = gDevTools.openToolboxForTab(target, "styleeditor");
+    let toolbox = aWindow.gDevTools.openToolboxForTab(target, "styleeditor");
     toolbox.once("styleeditor-ready", function(event, panel) {
       gChromeWindow = panel._panelWin;
       gChromeWindow.styleEditorChrome._alwaysDisableAnimations = true;
@@ -52,21 +57,6 @@ function launchStyleEditorChrome(aCallback, aSheet, aLine, aCol)
   }
 }
 
-function launchStyleEditorChromeFromWindow(aWindow, aCallback, aSheet, aLine, aCol)
-{
-  gChromeWindow = aWindow.StyleEditor.openChrome(aSheet, aLine, aCol);
-  if (gChromeWindow.document.readyState != "complete") {
-    gChromeWindow.addEventListener("load", function onChromeLoad() {
-      gChromeWindow.removeEventListener("load", onChromeLoad, true);
-      gChromeWindow.styleEditorChrome._alwaysDisableAnimations = true;
-      aCallback(gChromeWindow.styleEditorChrome);
-    }, true);
-  } else {
-    gChromeWindow.styleEditorChrome._alwaysDisableAnimations = true;
-    aCallback(gChromeWindow.styleEditorChrome);
-  }
-}
-
 function addTabAndLaunchStyleEditorChromeWhenLoaded(aCallback, aSheet, aLine, aCol)
 {
   gBrowser.selectedTab = gBrowser.addTab();