Windows/Clipboard: Application hangs when sending message to non-responsive clipboard viewer

Unfortunately, there is no simple way to reproduce this.

However, it is observed when debugging QML+C++ applications built with MSVC runtime in debug with Qt Creator on Windows using CDB:
There are situations in which the debuggee pops up multiple MSVC-runtime assert dialog windows (apparently multiple threads hitting on ASSERT().
Qt Creator then hangs when trying to copy text from its widgets.

(See also http://bugreports.qt.nokia.com/browse/QTCREATORBUG-3769)