What about to add editorValue property to ComboBox ?

a value which is currently in the editor.

If we want to set any input filter for a combobox
this property is useful.

It changes at every key input onto input field of editable combobox
just as text property of TextInputControl
or just like replaceText() of TextInputControl is invoked

Once I thought the method TextInputControl getEditor()
which gets a text input control if the combobox is editable

But the internal implementation should not be shown.