diff --git a/include/wx/msw/checklst.h b/include/wx/msw/checklst.h
index 73385b20da..4840d09253 100644
--- a/include/wx/msw/checklst.h
+++ b/include/wx/msw/checklst.h
@@ -88,6 +88,8 @@ protected:
   void OnKeyDown(wxKeyEvent& event);
   void OnLeftClick(wxMouseEvent& event);
 
+  wxSize DoGetBestSize() const;
+
 private:
   size_t    m_nItemHeight;  // height of checklistbox items (the same for all)
 
diff --git a/src/msw/checklst.cpp b/src/msw/checklst.cpp
index bebe3235f3..d6e48edde8 100644
--- a/src/msw/checklst.cpp
+++ b/src/msw/checklst.cpp
@@ -547,5 +547,13 @@ int wxCheckListBox::DoHitTestItem(wxCoord x, wxCoord y) const
   return nItem >= m_noItems ? wxNOT_FOUND : nItem;
 }
 
+
+wxSize wxCheckListBox::DoGetBestSize() const
+{
+    wxSize best = wxListBox::DoGetBestSize();
+    best.x += wxOwnerDrawn::GetDefaultMarginWidth();  // add room for the checkbox
+    return best;
+}
+
 #endif