Destroy DirectInput helper window during shutdown

src/blackinput/win/joystickwindows.cpp

@@ -168,6 +168,7 @@ namespace BlackInput
         m_joystickDevices.clear();
         m_directInput.reset();
         CoUninitialize();
+        destroyHelperWindow();
     }
 
     void ReleaseDirectInput(IDirectInput8 *obj)
@@ -252,6 +253,19 @@ namespace BlackInput
         return 0;
     }
 
+    void CJoystickWindows::destroyHelperWindow()
+    {
+        HINSTANCE hInstance = GetModuleHandle(nullptr);
+
+        if (helperWindow == nullptr) { return; }
+
+        DestroyWindow(helperWindow);
+        helperWindow = nullptr;
+
+        UnregisterClass(helperWindowClassName, hInstance);
+        helperWindowClass = 0;
+    }
+
     void CJoystickWindows::addJoystickDevice(const DIDEVICEINSTANCE *pdidInstance)
     {
         CJoystickDevice *device = new CJoystickDevice(m_directInput, pdidInstance, this);

src/blackinput/win/joystickwindows.h

@@ -123,6 +123,9 @@ namespace BlackInput
         //! Creates a hidden DI helper window
         int createHelperWindow();
 
+        //! Destroys a hidden DI helper window
+        void destroyHelperWindow();
+
         //! Add new joystick device
         void addJoystickDevice(const DIDEVICEINSTANCE *pdidInstance);