Hello Al,

You can see an example of how to collapse and expand the items from code from our documentation.

Regards,
Svetoslav Dimitrov
Progress Telerik

Hello,

I am attaching to the end of this post a potential workaround that can help start a treelist with all items expanded - to see this work select one item from the treelist, click the button below it to see the second treelist populate with some data.

This is not a feature yet, it relies on re-rendering the treelist by toggling its visibility with an if-block, and that having all data items with hierarchical binding will start them expanded at the moment. Such a workaround should be replaced with a real feature when it becomes available and I cannot guarantee it will work in all cases.

Regards,
Marin Bratanov
Progress Telerik