PVS-Studio warning V595 for wxWidgets

void wxAuiToolBar::OnRightDown(wxMouseEvent& evt)
{
  ...
  if (m_overflowSizerItem)
  {
    int dropdown_size =
      m_art->GetElementSize(wxAUI_TBART_OVERFLOW_SIZE);
    if (dropdown_size > 0 &&
      evt.m_x > cli_rect.width - dropdown_size &&
      evt.m_y >= 0 &&
      evt.m_y < cli_rect.height &&
      m_art)
    {
       return;
    }
  }
  ...
}

This suspicious code was found in wxWidgets project by PVS-Studio static code analyzer.
Warning message is:
V595 The 'm_art' pointer was utilized before it was verified against nullptr. Check lines: 2659, 2664. aui auibar.cpp 2659

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/