In general the RadComboBox does not have a built-in property that will set the height of the dropdown according to the number of the items that are inside it. Doyou use any custom implementation to achieve this behavior? If so, can you also clarify on your scenario. Meanwhile I can suggest that you also try the RadAutocompleteBox control (as referenced in my previous post) that have such built-in functionality that can be used out of the box.
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