--- a/toolkit/components/printingui/ipc/PrintProgressDialogParent.cpp
+++ b/toolkit/components/printingui/ipc/PrintProgressDialogParent.cpp
@@ -75,41 +75,43 @@ PrintProgressDialogParent::RecvDocURLCha
     mPrintProgressParams->SetDocURL(newURL);
   }
   return IPC_OK();
 }
 
 void
 PrintProgressDialogParent::ActorDestroy(ActorDestroyReason aWhy)
 {
+  // If IPC actor is destroyed, we can't send to child via IPC.
+  mActive = false;
 }
 
 mozilla::ipc::IPCResult
 PrintProgressDialogParent::Recv__delete__()
 {
   // The child has requested that we tear down the connection, so we set a
   // member to make sure we don't try to contact it after the fact.
   mActive = false;
   return IPC_OK();
 }
 
 // nsIObserver
 NS_IMETHODIMP
 PrintProgressDialogParent::Observe(nsISupports *aSubject, const char *aTopic,
                                    const char16_t *aData)
 {
-  if (aTopic && !strcmp(aTopic, "cancelled")) {
-    Unused << SendCancelledCurrentJob();
-  } else {
-    if (mActive) {
+  if (mActive) {
+    if (aTopic && !strcmp(aTopic, "cancelled")) {
+      Unused << SendCancelledCurrentJob();
+    } else {
       Unused << SendDialogOpened();
-    } else {
-      NS_WARNING("The print progress dialog finished opening, but communications "
-                 "with the child have been closed.");
     }
+  } else {
+    NS_WARNING("The print progress dialog finished opening, but communications "
+               "with the child have been closed.");
   }
 
   return NS_OK;
 }
 
 
 } // namespace embedding
 } // namespace mozilla