It seems really strange to me that we should have to add calls to LoadElementTree() every time AutoSize is enabled and a parent container isn't visible and we want to access basic layout properties for a control. Typically we want to ensure a layout is set before making a container visible so there are less calculations and drawing is faster and smoother - not such an issue nowadays but it's still best practice.
As a point of interest, I repeated the same process with ComboBox instead of RadDropDownList and all properties were perfectly accessible in typical .NET fashion.
May I request that this is handled internally in future? So when layout properties are requested but the layout hasn't being handled yet that it will get evaluated and then the correct values will be available?
Thanks for all your assistance Hristo, across the threads and support tickets I've learned quite a bit more about Telerik so I'm starting to get a better understanding of how to work with it.