fixed sorting the items which have indirect data (i.e. images set for open/closed state) and made indirect data handling much simpler and more efficient as a side effect

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@13164 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/treectrl.h

@@ -433,14 +433,13 @@ private:
 
     void DeleteTextCtrl();
 
-    // support for additional item images
-    friend class wxTreeItemIndirectData;
+    // support for additional item images which we implement using
+    // wxTreeItemIndirectData technique - see the comments in msw/treectrl.cpp
     void SetIndirectItemData(const wxTreeItemId& item,
-                             wxTreeItemIndirectData *data);
+                             class wxTreeItemIndirectData *data);
     bool HasIndirectData(const wxTreeItemId& item) const;
-
-    // the array storing all item ids which have indirect data
-    wxArrayTreeItemIds m_itemsWithIndirectData;
+    bool IsDataIndirect(wxTreeItemData *data) const
+        { return data->GetId().m_pItem == 0; }
 
     // the hash storing the items attributes (indexed by items ids)
     wxHashTable m_attrs;
@@ -454,6 +453,9 @@ private:
     // the starting item for selection with Shift
     WXHTREEITEM m_htSelStart;
 
+    friend class wxTreeItemIndirectData;
+    friend class wxTreeSortHelper;
+
     DECLARE_DYNAMIC_CLASS(wxTreeCtrl)
 };