mixed checkbox

 BOOL OnDrawItemValue(CDC& dc, CRect rcValue)
 {
  if (!m_bCheckBoxStyle)
   return FALSE;
  CRect rcSample(rcValue.left - 1, rcValue.CenterPoint().y - 6, rcValue.left - 1 + 13, rcValue.CenterPoint().y + 7);
  CXTPPropertyGridPaintManager* pPaintManager = m_pGrid->GetPaintManager();
  if (pPaintManager->m_buttonsStyle == xtpGridButtonsThemed && pPaintManager->m_themeButton.IsAppThemed())
  {
   int style = 
    GetReadOnly() 
     ? (isMultiValue() 
      ? CBS_MIXEDDISABLED 
      : (GetBool() ? CBS_CHECKEDDISABLED : CBS_UNCHECKEDDISABLED)
     ) 
     : (isMultiValue() 
      ? CBS_MIXEDNORMAL 
      : (GetBool() ? CBS_CHECKEDNORMAL : CBS_UNCHECKEDNORMAL)
     );
   pPaintManager->m_themeButton.DrawThemeBackground(dc, BP_CHECKBOX, style, rcSample, 0);
  }
  else
  {
   dc.DrawFrameControl(rcSample, DFC_BUTTON, DFCS_BUTTONCHECK |
    (GetReadOnly() ? DFCS_INACTIVE : 0) | (GetBool() ? DFCS_CHECKED : 0));
  }
  return TRUE;
 }