Highlight Specific Emoji

[Californian]

I'm using this for an emoji reaction UI and I'd like to have the emoji that have already been reacted still show up in the picker, but highlighted in one color if they've already selected it, or a different color if someone else has already selected it, or default color if it hasn't been selected.

I'd just exclude them from the picker, but this could confuse users because they might think that the emoji isn't valid.

I don't think this is currently doable without some intricate CSS, but it would be useful for me! I think it would be as easy as adding a field for a background highlight map.