Making A Side-Set Taskbar Smaller?

I've recently decided that I like the Windows Taskbar a lot better if it's on the left-hand side, rather than the bottom (and auto-hidden, but that's beside the point). For some reason, the smallest width I can drag it to is wide enough for tray icons to sit two to a row. I've seen taskbars smaller than that on the side, though, so I'm not sure what the problem is. I've made sure to select "Use small icons" in the settings, too, to no avail.