Event.button == 0 aways true

Hi guys, there is something wrong happening with my Editor Window, check the code:

using UnityEngine;
using UnityEditor;
using System.Collections;

public class NewMouseTest : EditorWindow
{
	[MenuItem ("Window/My Window2")]
    static void Init ()
	{
		NewMouseTest window = EditorWindow.GetWindow (typeof (NewMouseTest)) as NewMouseTest;
		
	}
	
	void OnGUI () 
	{
		Event e = Event.current;
		Debug.Log(e.button);
		wantsMouseMove = true;
	}
}

Turns out the Left Mouse Button(0) is being logged aways, no matter what, and with this I can’t check for clicks inside my windows, whats wrong with the script?

Screenshot of the logs:
http://d.pr/i/qvGO

Edit 1:
This piece of code will give the same result, aways true.

int counter = 0;
	
	void OnGUI () 
	{
		Event e = Event.current;
	
		if(e.isMouse && e.button == 0)
		{
			counter++;
		}
		
		GUILayout.Label(counter.ToString());
		
		wantsMouseMove = true;
	}

Try checking for Event.Current.type == EventType.MouseDown This is the way that they do it in the editor, which responds differently to users than regular code in game classes.