If I load my treeview, then apply .filter on the root dataSource, when I open my nodes, the sub-items are all displayed, they are not filtered.
But, it works if loadOnDemand = false.
You KNOW that bug, because in that sample, you specifically set the "loadOnDemand = false" option.
I was able to fix it by applying the "main" filter to my nodes dataSource (node.children), on the "expand" event.
But, I think you should fix it in your source code instead!