If I do the following, is only the second set of operations retained in the ClientChanges property?
var tree = $find("<%= RadTreeView1.ClientID %>");
tree.trackChanges();
// first set of client-side operations...
tree.trackChanges();
// second set of client-side operations...
tree.commitChanges();
var tree = $find("<%= RadTreeView1.ClientID %>");
tree.trackChanges();
// first set of client-side operations...
tree.trackChanges();
// second set of client-side operations...
tree.commitChanges();