Hi,
To have custom items in the header use the headerButtons array to define the buttons of a layoutPanel. There you can list the built-in buttons and custom ones. If you want your header item to be something else, not a button, you can replace the element.
Please see this demo to get familiar with the setting and replacing the item: https://codepen.io/Steevee222/pen/wvEqQBM
I hope this helps!
Best Regards,
Steven Peterson
Smart UI Team
https://www.htmlelements.com/