Prevent multi-select combobox to select the same option multiple times

[ChloeAidi]

Hello,

I am trying to implement a multiselect combobox with react. I can make it work perfectly with the mouse interaction, but with the use of the keyboard arrow + enter key, I don't manage to prevent the user from selecting an option multiple times (by pressing enter many times). Field value contains the selected option multiple times in its array.

The best work around I found for now is the deactivate the enter key, but I feel like it remove some useful functionnality :
<Combobox.Input onKeyDown={(e) => { if (e.code === 'Enter') { e.preventDefault(); } }} [...]

How would you handle this? Ideally I would like that the user can also remove an option by pressing enter when a preselected option is highlighted