diff --git a/vcl/inc/jsdialog/jsdialogmessages.hxx b/vcl/inc/jsdialog/jsdialogmessages.hxx
index 3958a702c..74448fd4f 100644
--- a/vcl/inc/jsdialog/jsdialogmessages.hxx
+++ b/vcl/inc/jsdialog/jsdialogmessages.hxx
@@ -10,6 +10,7 @@
 #pragma once
 
 #include <deque>
+#include <memory>
 #include <mutex>
 
 #include <rtl/ustring.hxx>
@@ -96,10 +97,13 @@ class JSDialogNotifyIdle final : public Idle
 
     std::deque<JSDialogMessageInfo> m_aMessageQueue;
     std::mutex m_aQueueMutex;
+    // False once destroyed: a send may close the dialog.
+    std::shared_ptr<bool> m_pAlive;
 
 public:
     JSDialogNotifyIdle(VclPtr<vcl::Window> aNotifierWindow, VclPtr<vcl::Window> aContentWindow,
                        const rtl::OUString& sTypeOfJSON);
+    ~JSDialogNotifyIdle() override;
 
     void Invoke() override;
 
diff --git a/vcl/jsdialog/jsdialogsender.cxx b/vcl/jsdialog/jsdialogsender.cxx
index 1ca544647..155fd554c 100644
--- a/vcl/jsdialog/jsdialogsender.cxx
+++ b/vcl/jsdialog/jsdialogsender.cxx
@@ -20,10 +20,13 @@ JSDialogNotifyIdle::JSDialogNotifyIdle(VclPtr<vcl::Window> aNotifierWindow,
     , m_aContentWindow(std::move(aContentWindow))
     , m_sTypeOfJSON(sTypeOfJSON)
     , m_bForce(false)
+    , m_pAlive(std::make_shared<bool>(true))
 {
     SetPriority(TaskPriority::POST_PAINT);
 }
 
+JSDialogNotifyIdle::~JSDialogNotifyIdle() { *m_pAlive = false; }
+
 void JSDialogNotifyIdle::forceUpdate() { m_bForce = true; }
 
 void JSDialogNotifyIdle::send(const OString& sMsg)
@@ -248,8 +251,18 @@ void JSDialogNotifyIdle::Invoke()
         std::swap(aMessageQueue, m_aMessageQueue);
     }
 
+    // A disposed dialog has nothing left to describe.
+    if ((m_aNotifierWindow && m_aNotifierWindow->isDisposed())
+        || (m_aContentWindow && m_aContentWindow->isDisposed()))
+        return;
+
+    const std::shared_ptr<bool> pAlive = m_pAlive;
     for (auto& rMessage : aMessageQueue)
     {
+        // The last send's client closed the dialog.
+        if (!*pAlive)
+            return;
+
         jsdialog::MessageType eType = rMessage.m_eType;
 
         if (m_sTypeOfJSON == "formulabar" && eType != jsdialog::MessageType::Action)