What you are doing there is finding the RadDropDownListElement that is nested inside the RadSchedulerNavigator. Most, if not all RadControls are made up of several elements. So a RadButton for example would have a button element, a border element, a fill primitive element and so on.
If you go to the designer and click on the smart tag, and look at "Edit UI Elements" then you will see a hierarchy of different elements. Each one of these elements can be controlled.
Hope this helps. Please remember to mark as answer so others can find the solution too and if you need more information, just let me know.