The LoadValue(true) function will be available in the release hotfix today. The InstantLookup mode will only lookup item when the user leave the textbox, by using the Enter key, LostFocus, or clicking the dropdown icon, it will not be available after every keystroke. 

This mode will also solve the fast typer scenario you are having in the earlier post. 

I am not sure about the conflict you are having in the LostFocus, perhaps if you could give us the snippet of the function we could help you solve the issue.

The snippet is for the WebGrid1_ButtonClick in the 4_Glenn.jpg attachment. In this case the ChildKey variable will be RetrieveClientLastSelectedObject KeyValues property. 

For the snippet to work, you will also need to use the RestoreExpandedChildRows="true" property in the LayoutSetting 

You could check the Nodes.IsPopulate property to ensure whether the TreeView has completed the loading process. If it has not set the timeout to wait for the TreeView to complete its process. Here is the snippet:

function WebTreeView1_OnInitialize(ctrlId) {      AlertNodesAfterComplete();     
}
function AlertNodesAfterComplete() {
    var treeview = ISGetObject("WebTreeView1");
    if (treeview.Nodes.IsPopulate) {
        WebTreeView_GetNodes();
        WebTreeView_GetArrayNodes();
    }
    else {
        setTimeout(function() { AlertNodesAfterComplete(); }, 10);
    }
}

It seems you will need to use timeout function to wait for the WebTreeView to finish the initializing process to retrieve the correct value. In the attached modified sample, I use 500ms timeout to make sure the WebTreeView finish the initializing process before reporting the nodes length.