Combobox items not showing when Windows DPI changed

Question

I have a CComboBox based Custom ComboBox with CBS_OWNERDRAWVARIABLE. The items in Comboxbox are shown when the DPI is 96. But when DPI is greater 96 then items are not shown. I could not figure out what could be the issue. When I change CBS_OWNERDRAWVARIABLE to CBS_OWNERDRAWFIXED then everything is working fine.

When Scale & Layout value is 100% everything works fine. But if the scale percent is more than 100 then the items are not shown.

when scale percent = 100

when scale percent greater than 100

My code snippet for DrawItem & MeasureItem.

void CMyComboBox::MeasureItem(LPMEASUREITEMSTRUCT lpMeasureItemStruct)
{
   if (lpMeasureItemStruct->itemID != -1)
   {
     lpMeasureItemStruct->itemHeight = 16; 
   }
}

void CMyComboBox::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{
   ASSERT(lpDrawItemStruct->CtlType == ODT_COMBOBOX);
   LPCTSTR lpszText = (LPCTSTR)lpDrawItemStruct->itemData;
   ASSERT(lpszText != NULL);
   CDC dc;

   dc.Attach(lpDrawItemStruct->hDC);

   // Save these value to restore them when done drawing.
   COLORREF crOldTextColor = dc.GetTextColor();
   COLORREF crOldBkColor = dc.GetBkColor();

   // If this item is selected, set the background color
   // and the text color to appropriate values. Erase
   // the rect by filling it with the background color.
   if ((lpDrawItemStruct->itemAction & ODA_SELECT) &&
       (lpDrawItemStruct->itemState & ODS_SELECTED))
   {
      dc.SetTextColor(::GetSysColor(COLOR_HIGHLIGHTTEXT));
      dc.SetBkColor(::GetSysColor(COLOR_HIGHLIGHT));
      dc.FillSolidRect(&lpDrawItemStruct->rcItem, ::GetSysColor(COLOR_HIGHLIGHT));
   }
   else
   {
      dc.FillSolidRect(&lpDrawItemStruct->rcItem, crOldBkColor);
   }

   // Draw the text.
   dc.DrawText(
       lpszText,
       (int)_tcslen(lpszText),
       &lpDrawItemStruct->rcItem,
       DT_CENTER | DT_SINGLELINE | DT_VCENTER);

   // Reset the background color and the text color back to their
   // original values.
   dc.SetTextColor(crOldTextColor);
   dc.SetBkColor(crOldBkColor);

   dc.Detach();
}