If you create a dropdown menu and it is low in the list of options in the menu, it can get cut off. In this example, there are four settings under the dropdown, but if there were only two then only about half of the dropdown would be visible. If the dropdown was the last option, then it would be virtually impossible to interact with.
https://www.dropbox.com/s/enwmegl3xormkql/mcm-dropdown-cutoff.png?dl=0