Application hangs up when keyboard layout is changed in the context of QNetworkAccessManager::authenticationRequired

Description

This sample application sends GET-request and web-server requires authentication. GUI dialog is created in slot connected to QNetworkAccessManager::authenticationRequired. If user changes keyboard layout (by shortcut or mouse) application will hang up. There is no any freezing if keyboard layout is changed outside QNetworkAccessManager::authenticationRequired context.

This is a Windows-only issue.

How to reproduce

1) Enable advanced text services by checking "Extend support of advanced text services to all programs" in a Windows settings dialog "Text Services and Input Languages".
2) In an attached sample application change URL from the 'localhost' to any web-server which requires an authentication.
3) Compile & run.
4) Switch keyboard layout while in a dialog.

Workaround

1) Disable Windows IME (input method editor) for this application by uncommenting this line in main.cpp:

 // ImmDisableIME(-1); 

2) Check "Turn of advanced text services" in a Windows settings dialog "Text Services and Input Languages". This solution does not work on some Windows XP installations.

Additional

I guess this is a similar issue: https://bugreports.qt-project.org/browse/QTCREATORBUG-418