A small component which ensures that a Unity Dropdown, after having a value selected, will show that value at the top when reopening the dropdown.

DropdownFixer.cs

using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

public class DropdownFixer : MonoBehaviour, IPointerClickHandler
{
	public Dropdown Dropdown;
	public int ElementHeight = 50; //The height of the elements in your Dropdown

	public void OnPointerClick(PointerEventData eventData)
	{
		RectTransform[] transforms = GetComponentsInChildren<RectTransform>();
		RectTransform content = null;

		foreach(RectTransform t in transforms)
		{
			if(t.name == "Content")
			{
				content = t;
				break;
			}
		}

		if (content == null) return;

		int index = Dropdown.value;
		content.localPosition = content.localPosition + Vector3.up * index * ElementHeight;
	}
}