Yeah, that doesn't sound like the intended behavior. It's probably the fact that the dropdown is scrolling on a screen that is too small. I'll try it on my netbook.
Try the "map" menu as a workaround. It should have shortcuts to all the major map types, and less choices since the different zoom levels aren't spelled out. Learn the keyboard shortcuts, too, they are quite handy for flipping between map types.
I'll see if I can figure anything out on the scrolling drop down. Thanks for the post.