In MongoDB Compass, when I use the Drop Index functionality you get when clicking the "trash can" icon next to an index in the Indexes list on a collection, it shows a red "!" triangle icon in the upper left. That icon is used here to mean "Caution! You are about to do something dangerous!", as confirmed in Support case https://support.mongodb.com/case/01122132.

I think it's more conventional to use red icons, especially "!" or triangles like this, to indicate that an error has occurred, and warnings or cautions are more conventionally indicated in yellow. (There's probably some UI/UX documents or standards out there that cover this, but I don't know UI/UX that well.) Maybe this icon should be yellow instead? And only change to red if there was an error performing a requested Drop Index action?

Cheers,
Andrew