diff --git a/browser/devtools/commandline/test/browser_cmd_screenshot_perwindowpb.js b/browser/devtools/commandline/test/browser_cmd_screenshot_perwindowpb.js
index 0f0aa13ce7e..37ae74cfbe2 100644
--- a/browser/devtools/commandline/test/browser_cmd_screenshot_perwindowpb.js
+++ b/browser/devtools/commandline/test/browser_cmd_screenshot_perwindowpb.js
@@ -11,6 +11,15 @@ let FileUtils = Cu.import("resource://gre/modules/FileUtils.jsm", {}).FileUtils;
 function test() {
   waitForExplicitFinish();
 
+  let windowsToClose = [];
+  Services.prefs.setIntPref("browser.startup.page", 0);
+  registerCleanupFunction(function() {
+    Services.prefs.clearUserPref("browser.startup.page");
+    windowsToClose.forEach(function(win) {
+      win.close();
+    });
+  });
+
   function testOnWindow(aPrivate, aCallback) {
     let win = OpenBrowserWindow({private: aPrivate});
     win.addEventListener("load", function onLoad() {
@@ -20,29 +29,25 @@ function test() {
   };
 
   testOnWindow(false, function(win) {
+    info("Testing on public window");
+    windowsToClose.push(win);
     DeveloperToolbarTestPW.test(win, TEST_URI, [ testInput, testCapture ], null, function() {
-      win.close();
       testOnWindow(true, function(win) {
-        executeSoon(function() {
-          DeveloperToolbarTestPW.test(win, TEST_URI, [ testInput, testCapture ], null, function() {
-            win.close();
-            finish();
-          });
-        })
+        info("Testing on private window");
+        windowsToClose.push(win);
+        DeveloperToolbarTestPW.test(win, TEST_URI, [ testInput, testCapture ], null, finish);
       });
     });
   });
-
 }
 
-function testInput(aWindow) {
+function testInput(aWindow, aCallback) {
   helpers_perwindowpb.setInput('screenshot');
   helpers_perwindowpb.check({
     input:  'screenshot',
     markup: 'VVVVVVVVVV',
     status: 'VALID',
-    args: {
-    }
+    args: { }
   });
 
   helpers_perwindowpb.setInput('screenshot abc.png');
@@ -85,9 +90,11 @@ function testInput(aWindow) {
       selector: { value: aWindow.content.document.getElementById("testImage")},
     }
   });
+
+  aCallback();
 }
 
-function testCapture(aWindow) {
+function testCapture(aWindow, aCallback) {
   function checkTemporaryFile() {
     // Create a temporary file.
     let gFile = FileUtils.getFile("TmpD", ["TestScreenshotFile.png"]);
@@ -100,6 +107,13 @@ function testCapture(aWindow) {
     }
   }
 
+  let captureTest = 3;
+  function captureTestFinish() {
+    if (captureTest == 0) {
+      aCallback();
+    }
+  }
+
   function checkClipboard() {
     try {
       let clipid = Ci.nsIClipboard;
@@ -137,6 +151,8 @@ function testCapture(aWindow) {
 
   executeSoon(function() {
     ok(checkTemporaryFile(), "Screenshot got created");
+    captureTest--;
+    captureTestFinish();
   });
 
   DeveloperToolbarTestPW.exec(aWindow, {
@@ -153,6 +169,7 @@ function testCapture(aWindow) {
   });
 
   ok(checkClipboard(), "Screenshot got created and copied");
+  captureTest--;
 
   DeveloperToolbarTestPW.exec(aWindow, {
     typed: "screenshot --clipboard",
@@ -168,4 +185,6 @@ function testCapture(aWindow) {
   });
 
   ok(checkClipboard(), "Screenshot present in clipboard");
+  captureTest--;
+  captureTestFinish();
 }
diff --git a/browser/devtools/commandline/test/helpers_perwindowpb.js b/browser/devtools/commandline/test/helpers_perwindowpb.js
index 227fe692b25..1eba91b6cd4 100644
--- a/browser/devtools/commandline/test/helpers_perwindowpb.js
+++ b/browser/devtools/commandline/test/helpers_perwindowpb.js
@@ -393,7 +393,6 @@ DeveloperToolbarTestPW.test = function DTTPW_test(aWindow, uri, target, isGcli,
     if (appMenuItem) {
       appMenuItem.hidden = true;
     }
-
     // leakHunt({ DeveloperToolbar: DeveloperToolbar });
   };
 
@@ -408,13 +407,12 @@ DeveloperToolbarTestPW.test = function DTTPW_test(aWindow, uri, target, isGcli,
     appMenuItem.hidden = false;
   }
 
-  aWindow.gBrowser.selectedTab = aWindow.gBrowser.addTab();
-  aWindow.content.location = uri;
-
-  let tab = aWindow.gBrowser.selectedTab;
-  let browser = aWindow.gBrowser.getBrowserForTab(tab);
-
-  var onTabLoad = function() {
+  let browser = aWindow.gBrowser.selectedBrowser;
+  browser.addEventListener("load", function onTabLoad() {
+    if (aWindow.content.location.href != uri) {
+      browser.loadURI(uri);
+      return;
+    }
     browser.removeEventListener("load", onTabLoad, true);
 
     DeveloperToolbarTestPW.show(aWindow, function() {
@@ -430,35 +428,41 @@ DeveloperToolbarTestPW.test = function DTTPW_test(aWindow, uri, target, isGcli,
 
       if (Array.isArray(target)) {
         try {
-          target.forEach(function(func) {
-            var args = isGcli ? [ options ] : [ aWindow ];
-            func.apply(null, args);
-          });
-          cleanup();
-          aCallback();
-        }
-        catch (ex) {
+          var args = isGcli ? options : aWindow;
+          var targetCount = 0;
+          function callTarget() {
+            if (targetCount < target.length) {
+              info("Running target test: " + targetCount);
+              target[targetCount++](args, callTarget);
+            } else {
+              info("Clean up and continue test");
+              cleanup();
+              aCallback();
+            }
+          }
+          callTarget();
+        } catch (ex) {
           ok(false, "" + ex);
           DeveloperToolbarTestPW._finish(aWindow);
           throw ex;
         }
-      }
-      else {
+      } else {
         try {
-          target(aWindow);
-          cleanup();
-          aCallback();
-        }
-        catch (ex) {
+          target(aWindow, function() {
+            info("Clean up and continue test");
+            cleanup();
+            aCallback();
+          });
+        } catch (ex) {
           ok(false, "" + ex);
           DeveloperToolbarTestPW._finish(aWindow);
           throw ex;
         }
       }
     });
-  }
+  }, true);
 
-  browser.addEventListener("load", onTabLoad, true);
+  browser.loadURI(uri);
 };
 
 DeveloperToolbarTestPW._outstanding = [];