TreeView Demo Advances - TreeView With CheckBox shows no expand collapse

Rowan
Hi,
When I try to run the code of the example Advances - TreeView With CheckBox on my website, it does not show any expand or collapse buttons, so it does not seem possible to expand the nodes in the tree. What have I done wrong?
See http://www.sylvesterbradley.org/checkbox.php
Thanks - Rowan
Posted Mar 28, 2016 Kool