how can copy the Item but not cut it on the Drag and Drop ?

[mhubert]

Ok -- thanks that was one thing.

The second thing that needed changing is the function needs to be applied to the other tree

     myfavreport.on('beforenodedrop', function(e){
      var n = e.dropNode; // the node that was dropped
   var copy = new Ext.tree.TreeNode( // copy it
            Ext.apply({}, n.attributes) 
          );
     e.dropNode = copy; // assign the copy as the new dropNode
  });

below is a trick to prvent duplicating nodes dragged from inside the tree. This allows user sorting but prevents making additional copies

     myfavreport.on('beforenodedrop', function(e){
      var n = e.dropNode; // the node that was dropped
   if (e.source.el !=this.el) {
       var copy = new Ext.tree.TreeNode( // copy it
              Ext.apply({}, n.attributes) 
            );
       e.dropNode = copy; // assign the copy as the new dropNode
   }
  });