Enable easy sideways scrolling in wide modals

My team uses quite a lot of Labels for one column and I frequently find it’s awkward to scroll horizontally inside of the modal that appears to select one of these labels. It would be nice to afford the user perhaps an ability to roll the scroll wheel inside the modal to scroll sideways, to move the mouse to the edge, to middle-click, or some other way that’s faster than clumsily trying to find the horizontal scroll bar and drag it over.