Option passed to a control to specify a maximum height.

	// Draws a window you can resize between 80px and 200px height
	// Just click the box inside the window and move your mouse
	private var windowRect : Rect = Rect (10, 10, 100, 100);
	private var scaling : boolean = false;
	
	function OnGUI () {
		windowRect = GUILayout.Window (0, windowRect, ScalingWindow, "resizeable", 
					       GUILayout.MinHeight(80), GUILayout.MaxHeight(200));
	}
	
	function ScalingWindow (windowID : int) {
		GUILayout.Box("", GUILayout.Width(20), GUILayout.Height(20));
		if (Event.current.type == EventType.MouseUp) {
			scaling = false;
		}
		else if (Event.current.type == EventType.MouseDown && 
			 GUILayoutUtility.GetLastRect().Contains(Event.current.mousePosition)) {
			scaling = true;
		}
		
		if (scaling) {
			windowRect = Rect (windowRect.x, windowRect.y, 
				   windowRect.width + Event.current.delta.x, windowRect.height + Event.current.delta.y);
		}
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    private Rect windowRect = new Rect(10, 10, 100, 100);
    private bool scaling = false;
    void OnGUI() {
        windowRect = GUILayout.Window(0, windowRect, ScalingWindow, "resizeable", GUILayout.MinHeight(80), GUILayout.MaxHeight(200));
    }
    void ScalingWindow(int windowID) {
        GUILayout.Box("", GUILayout.Width(20), GUILayout.Height(20));
        if (Event.current.type == EventType.MouseUp)
            scaling = false;
        else
            if (Event.current.type == EventType.MouseDown && GUILayoutUtility.GetLastRect().Contains(Event.current.mousePosition))
                scaling = true;
            
        if (scaling)
            windowRect = new Rect(windowRect.x, windowRect.y, windowRect.width + Event.current.delta.x, windowRect.height + Event.current.delta.y);
        
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	private windowRect as Rect = Rect(10, 10, 100, 100)

	private scaling as bool = false

	def OnGUI() as void:
		windowRect = GUILayout.Window(0, windowRect, ScalingWindow, 'resizeable', GUILayout.MinHeight(80), GUILayout.MaxHeight(200))

	def ScalingWindow(windowID as int) as void:
		GUILayout.Box('', GUILayout.Width(20), GUILayout.Height(20))
		if Event.current.type == EventType.MouseUp:
			scaling = false
		elif (Event.current.type == EventType.MouseDown) and GUILayoutUtility.GetLastRect().Contains(Event.current.mousePosition):
			scaling = true
		if scaling:
			windowRect = Rect(windowRect.x, windowRect.y, (windowRect.width + Event.current.delta.x), (windowRect.height + Event.current.delta.y))