On multiple select the add item link always shows

[koenpunt]

When having a multiple select the create option link always appears, this is because the option, when selected, is not in the select anymore.

[cgatesman]

I was going to create a similar issue, so I'll just comment, here, instead.

I ran into what I think you're describing here when using display_selected_options="false" along with create-option. If you type an item that is already selected, it will give you the option to create the item, because it is not in the list. However, it's just not being shown, because it's selected and I'm using the display_selected_options="false" option.