treepanel removechildren problem

Hi

I am using async tree loading. When the screen loads initialy the folder icon plus the + sign is displayed. The user click the + sign and the next level is displayed via async.

I remove all the children from the root node with the removechildren function (so that new data can be loaded for the root node of the tree) but it comes back with the leaf node icon without a + sign. When I double click on the leaf node it loads the new data into the tree that is supposed to be loaded with the + sign of the root node.

Is there a way that when I remove all the children from the root node with the removechildren function that the folder icon is displayed plus the + sign so that the user can just click on the + sign to load the next level

Thanks
Richardt