Feature request: Disable adding the same item multiple times in AssetList

In an TYPO3.Neos.NodeTypes.AssetList I am able to select the same item multiple times.
For me, this feels like a bug.

I think, it should either be disallowed to select the same asset multiple times or at least there should be an alert, asking the user if he/she reallly wants to add the same asset again.

Especially on longer lists it is not that easy to see, if I have already added a specific asset.