items.overflowTemplate String|Function
Specifies what element will be added in the command overflow popup. Applicable only for items that have a template.
Example
<div id="toolbar"></div>
<script>
$("#toolbar").kendoToolBar({
items: [
{
template: "<span>Toolbar template</span>",
overflowTemplate: "<span>Overflow template</span>"
}
]
});
</script>