I have customized the dmry tree menu plugin by Hakan Demiray so that it will do what I want. It’s a great plugin, but I needed it to work a little differently. I wanted it to automatically open the child nodes of the selected menu item, so that users can see what is there.
I have submitted my modifications to the plugin for possibly inclusion in the next version. In the meantime I will make my version available for download here.
Update: Here is some code to add OpenAll and CloseAll links (in response to the comment by Alby below).
Just put this code after the menu call in your page template (mine is in sidebar.php). If you want to you can use images or buttons instead of simple text for the link.
Posted by Ken in Wordpress







