a few month ago I reported a incorrect functionality in CXTPPropertyGridItemDate::SetValue() ( http://forum.codejock.com/forum_posts.asp?TID=6404 - http://forum.codejock.com/forum_posts.asp?TID=6404 ). This failure is still present in 12.0 release (see red marked part):

 

void CXTPPropertyGridItemDate::SetValue(CString strValue)
{
 COleDateTime dt;
 TRY
 {
  if (ParseDateTime(dt, strValue))
  {
   SetDate(dt);
  }
  else if (dt.ParseDateTime(strValue, VAR_DATEVALUEONLY, LANG_RUSSIAN))
  {
   SetDate(dt);
  }
  else if (!m_strNullValue.IsEmpty())
  {
   COleDateTime dtNull;
   dtNull.SetStatus(COleDateTime::null);

   SetDate(dtNull);
  }
 }
 CATCH(COleException, e)
 {

 }
 END_CATCH
}