A little update, @cpradio made a plugin that works, I was able to add some buttons myself, it’s pretty easy if some people want to add theirs : GitHub - cpradio/discourse-plugin-spoiler-ui: Spoiler Composer Button for Discourse
Minor bug, I don’t know if it’s the composer or the plugin, but the spoiler bbcode doesn’t work on the preview, but works fine otherwise
Test
Also, not really a bug, but an observation. When we used an emoji (via the modal), the old editor added one space before and one after the emoji, not in the new one. Not really a problem though
edit : and finally, a little problem for european users, when we type the euro symbol (€ - shortcut : ALT Gr + E) it also opens the emoji modal.