Adding a button to ComboBox

How to create a ComboxBox like this ? it has a button at the end to let user add values on the fly

It’s not supported to add custom content like this in the combo box overlay. The prefix could be used for such a button, or using the official custom item stuff described in the docs or as last solution: creating a component renderer and a placeholder item which is rendered like this and all other items are just returned as Spans

I think the prefix is OK for now