Option passed to a control to allow or disallow horizontal expansion.

	function OnGUI () {
		GUILayout.BeginVertical();
		GUILayout.Button("Short Button", GUILayout.ExpandWidth(false));
		GUILayout.Button("Very very long Button");
		GUILayout.EndVertical();
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void OnGUI() {
        GUILayout.BeginVertical();
        GUILayout.Button("Short Button", GUILayout.ExpandWidth(false));
        GUILayout.Button("Very very long Button");
        GUILayout.EndVertical();
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def OnGUI() as void:
		GUILayout.BeginVertical()
		GUILayout.Button('Short Button', GUILayout.ExpandWidth(false))
		GUILayout.Button('Very very long Button')
		GUILayout.EndVertical()