Dropdown disable blocker

Dropdown script creates blocker element automatically to prevent not clicking dropdown options. I don’t want the blocker, are there any built-in option to disable it?

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GIF: http://i.imgur.com/bPBzpFO.gif

Hi. I don’t know the built in potion, but I fix the same problem by this scripts. My unity version is 5.6.4f.

UnityEngine.UI.Dropdown.DestroyObject(GameObject.Find("Blocker"));