PVS-Studio warning V547 for WinMerge

BOOL CCrystalEditView::
DoDropText (COleDataObject * pDataObject,
            const CPoint & ptClient)
{
  ...
  UINT cbData = (UINT) ::GlobalSize (hData);
  UINT cchText = cbData / sizeof(TCHAR) - 1;
  if (cchText < 0)
    return FALSE;
  ...
}

This suspicious code was found in WinMerge project by PVS-Studio static code analyzer.
Warning message is:
V547 Expression 'cchText < 0' is always false. Unsigned type value is never < 0. Merge ccrystaleditview.cpp 1135

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/