Multi-select text input can't have options with the same name

[FionanaLin]

Hi, I was following the code that the live demo page shown for multi-select text input.
However, if I make two or more options with the same value, they will all be deleted at once when I just want to delete one of them.
And if I make options with the same value first then make a different one, when trying to delete the options with the same value,
this happens.

(This is the live demo page)

Since I got this warning,
Warning: Encountered two children with the same key, 123-123.
I guess the problem is that these options with the same value also have the same key.
I've seen that this problem have been discussed and said it was fixed, but I see no change.
Could somebody tell me how to fix this?