[SHELL32]: In some rare cases, pressing Alt-F4 in ReactOS when the desktop was on focus, just removed the desktop icons. The underlying "progman" window was indeed killed. Sending a WM_CLOSE message to it should not close it directly, but instead prompt the user with the Shutdown dialog. Tests on Windows show that it's indeed the case.

This fix completes r65557.
CORE-4351 CORE-8864

svn path=/trunk/; revision=71533

reactos/dll/win32/shell32/shelldesktop/CDesktopBrowser.cpp

@@ -536,6 +536,9 @@ LRESULT CALLBACK CDesktopBrowser::ProgmanWindowProc(IN HWND hwnd, IN UINT uMsg,
                 break;
             }
 
+            case WM_CLOSE:
+                return pThis->_NotifyTray(TWM_DOEXITWINDOWS, 0, 0);
+
             case WM_EXPLORER_OPEN_NEW_WINDOW:
                 TRACE("Proxy Desktop message 1035 received.\n");
                 SHOnCWMCommandLine((HANDLE)lParam);