diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index e824c9541..5346ba11d 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -9411,7 +9411,9 @@ void
 nsGlobalWindow::SetActive(bool aActive)
 {
   nsPIDOMWindow::SetActive(aActive);
-  NotifyDocumentTree(mDoc, nullptr);
+  if (mDoc) {
+    NotifyDocumentTree(mDoc, nullptr);
+  }
 }
 
 void nsGlobalWindow::SetIsBackground(bool aIsBackground)