Hello All,
I also tried this but not worked, But i have analyse that it's happening due to kanban click class.
There is a class in kanban form oe_kanban_global_click. When you click on anywhere in kanban (not clicked in action link like View Sales Order, Opportunities in contacts kanban) it's open form view of that record. So you need to improve that behavior.
You can do the JS stuff to achieve this.
add custom class in button and on click of that button alert using JS.
I hope this will helpful for you.
Regards
Haresh Kansara
Did you find the solution?