I've got a Tree and I'm using a TreeLoader to load nodes asynchronously. The backend data takes a few seconds to generate, so I need to show some feedback to show that the child nodes are loading. In GXT 2.x there was a spinner icon to indicate this, however this doesn't seem to be supported in GXT 3.

Looking in the source for TreeView.java I see:

  public void onLoading(TreeNode<M> node) {
    // onIconStyleChange(node, IconHelper.createStyle("x-tree3-loading"));
Does this mean this hasn't been implemented, or am I supposed to do something with this myself? There doesn't seem to be anything in TreeAppearance render a loading node.