PVS-Studio warning V540 for Fennec Media Project

int JoiningProc(HWND hwnd,UINT uMsg,
  WPARAM wParam,LPARAM lParam)
{
  ...
  OPENFILENAME  lofn;
  memset(&lofn, 0, sizeof(lofn));
  ...
  lofn.lpstrFilter = uni("All Files (*.*)\0*.*");
  ...
}

This suspicious code was found in Fennec Media Project project by PVS-Studio static code analyzer.
Warning message is:
V540 Member 'lpstrFilter' should point to string terminated by two 0 characters. base windows.c 5309

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/