ComboBox - adding new item

Hello guys!

I’m trying to suit a combobox to my needs, and here are what i want to ask:

– is it possible to add a new item just in a client’s browser? I want to allow users add new items, but only when they submit a form. Because now if I write a new string to the combobox it will disappear after losing focus.
I implemented a NewItemHandler but there is no way to correct misspellings - new items is just added at the end of the list.

– i set off FilteringMode, but when i’m writing in the combobox a list of strings opens. Is it suppose to be like this?

Thank you!