diff --git a/browser/base/content/tabbrowser.xml b/browser/base/content/tabbrowser.xml
index d4df769127c..b450cac9669 100644
--- a/browser/base/content/tabbrowser.xml
+++ b/browser/base/content/tabbrowser.xml
@@ -1599,6 +1599,11 @@
             evt.initUIEvent("TabClose", true, false, window, aTabWillBeMoved ? 1 : 0);
             aTab.dispatchEvent(evt);
 
+            // Prevent this tab from showing further dialogs, since we're closing it
+            var windowUtils = browser.contentWindow.QueryInterface(Ci.nsIInterfaceRequestor).
+                              getInterface(Ci.nsIDOMWindowUtils);
+            windowUtils.preventFurtherDialogs();
+
             // Remove the tab's filter and progress listener.
             const filter = this.mTabFilters[aTab._tPos];
 #ifdef MOZ_E10S_COMPAT
diff --git a/dom/base/nsDOMWindowUtils.cpp b/dom/base/nsDOMWindowUtils.cpp
index 5ae971245d3..669302005e3 100644
--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -1936,3 +1936,8 @@ nsDOMWindowUtils::CheckAndClearPaintedState(nsIDOMElement* aElement, bool* aResu
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDOMWindowUtils::PreventFurtherDialogs() {
+  mWindow->PreventFurtherDialogs();
+  return NS_OK;
+}
diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index 52211ee2540..e49b89d31ea 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -2627,10 +2627,7 @@ nsGlobalWindow::AreDialogsBlocked()
 
   topWindow = topWindow->GetCurrentInnerWindowInternal();
 
-  return !topWindow ||
-         (topWindow->mDialogDisabled &&
-          (topWindow->GetPopupControlState() > openAllowed ||
-           topWindow->mDialogAbuseCount >= MAX_DIALOG_COUNT));
+  return !topWindow || topWindow->mDialogDisabled;
 }
 
 bool
diff --git a/dom/interfaces/base/nsIDOMWindowUtils.idl b/dom/interfaces/base/nsIDOMWindowUtils.idl
index 09dd00d6dc4..438aefc0051 100644
--- a/dom/interfaces/base/nsIDOMWindowUtils.idl
+++ b/dom/interfaces/base/nsIDOMWindowUtils.idl
@@ -926,4 +926,9 @@ interface nsIDOMWindowUtils : nsISupports {
    */
   boolean checkAndClearPaintedState(in nsIDOMElement aElement);
 
+  /**
+   * Prevent this window (and any child windows) from displaying any further
+   * dialogs (e.g. window.alert()).
+   */
+  void preventFurtherDialogs();
 };