FindNode() must return m_root for wxDataViewItem(0)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@58248 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/datavgen.cpp

@@ -2543,6 +2543,9 @@ wxDataViewTreeNode * wxDataViewMainWindow::FindNode( const wxDataViewItem & item
     if( model == NULL )
         return NULL;
         
+    if (!item.IsOk())
+        return m_root;
+
     //Compose the a parent-chain of the finding item
     ItemList list;
     list.DeleteContents( true );
@@ -2743,6 +2746,7 @@ static void BuildTreeHelper( wxDataViewModel * model,  wxDataViewItem & item, wx
 
     wxDataViewItemArray children;
     unsigned int num = model->GetChildren( item, children);
+    
     unsigned int index = 0;
     while( index < num )
     {