The element with class "k-list-container" gets a different class applied depending on whether the dropdown is opened above or below the DropDownList's input area. So when it opens above the input the class we use is "k-state-border-down", when it opens below the input the class is "k-state-border-up". See the following short screencast
showing how the dropdowns of two DropDownLists initialized with/without MVVM are rendered. The classes applied to both widgets are identical and are correct. The dojo
example used to record the screencast.