PVS-Studio warning V512 for NetXMS

typedef WCHAR TCHAR, *PTCHAR;

#define MAX_TOOLBOX_TITLE  64

TCHAR m_szTitle[MAX_TOOLBOX_TITLE];

CToolBox::CToolBox()
{
  memset(m_szTitle, 0, MAX_TOOLBOX_TITLE);
}

This suspicious code was found in NetXMS project by PVS-Studio static code analyzer.
Warning message is:
V512 A call of the 'memset' function will lead to underflow of the buffer 'm_szTitle'. toolbox.cpp 28

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/