wxGUI/mapwindow: tree is still needed for map display although it is not needed for map window (fix bug in nviz from https://trac.osgeo.org/grass/changeset/57243)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@57245 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/lmgr/layertree.py

@@ -163,7 +163,7 @@ class LayerTree(treemixin.DragAndDrop, CT.CustomTreeCtrl):
                                    id = wx.ID_ANY, pos = pos,
                                    size = globalvar.MAP_WINDOW_SIZE,
                                    style = wx.DEFAULT_FRAME_STYLE,
-                                   notebook = self.notebook,
+                                   tree=self, notebook=self.notebook,
                                    lmgr = self.lmgr, page = self.treepg,
                                    Map = self.Map)