diff -Nur spatialite_gui-1.4.0/TableTree.cpp spatialite_gui-1.4.0-wxtree/TableTree.cpp
--- spatialite_gui-1.4.0/TableTree.cpp	2010-11-12 15:37:58.000000000 +0100
+++ spatialite_gui-1.4.0-wxtree/TableTree.cpp	2011-10-27 00:57:46.639983851 +0200
@@ -393,7 +393,7 @@
   wxPoint pt = event.GetPoint();
   if (item == Root)
     {
-      CurrentItem = NULL;
+      CurrentItem = wxTreeItemId();
       menuItem = new wxMenuItem(menu, Tree_Refresh, wxT("&Refresh"));
       menu->Append(menuItem);
       menu->AppendSeparator();
@@ -413,7 +413,7 @@
   MyObject *obj = (MyObject *) GetItemData(item);
   if (obj == NULL)
     {
-      CurrentItem = NULL;
+      CurrentItem = wxTreeItemId();
       menuItem = new wxMenuItem(menu, Tree_Refresh, wxT("&Refresh"));
       menu->Append(menuItem);
       menu->AppendSeparator();