It's mostly a bad habit born of years of slow computers, but when clicking into the Discord window to give it keyfocus I tend to double click and have already sent like four accidental reactions. It'd be nice to have a way to hide that panel behind a first button for trigger happy people like me.
Also tangentially related, the new UI seems oddly unresponsive with hardware acceleration on. There was a pretty pronounced lag between cursor movement and messages being highlighted before I turned it off. I have a 1080ti, so that seems pretty contrary to what I'd expect to be the case.