CTRL+drag to add groups to selection in DE?

Hey y'all, I'm finally getting ready to make the switch from HD to DE (starting to get to a skill level where finding lobbies is getting tricky in my time zone). I've been playing a few matches against the AI to get set up with my hotkeys and get used to shift-queueing (wow what a great feature) and I've been finding that I can't hold CTRL and drag to add a few additional units to my selection; I have to CTRL+click them individually. This takes longer and throws me off, especially if I'm trying to add a few extra villagers to a quick task. Is there an option in the settings to turn this on? Or is this feature just disabled?